So the issue seems to be that you've run out of your dose early. Did you happen to document what happened with the plane somehow (pictures or something)? This is actually a not at all uncommon issue with traveling by plane (when the pressure changes if they're taken as checked baggage).
I'd advise you to contact you home clinic, tell them what happen, and arrange a guest dosing for the time you'll be on vacation. Some clinics are better about this than others, but it all boils down the relationships you have with your clinic director and doctor. If you've been doing well enough to get a week of take homes, changes are they'll be more understanding with you than someone who was failing drug tests recently.
Now, if that doesn't turn out to work, there are three medications you can get yourself prescribed to treat the majority of the withdrawal symptoms (which really take about five days to present in their full shittiness). Those being diazepam (or clonazepam, but IME diazepam works a little better), clonidine and gabapentin. You'll probably have to dose high on the gabaneptin, but you should be able to get away with 10mg diazepam twice a day, and clonidine 0.2mg once or twice a day (just be careful about sitting down or laying down and standing back up after you've taken clonidine, and try to monitor your BP with it).
I don't mean to scare you, but withdrawal from methadone begins to fully present around day five like I said, so you're only getting a taste if you're on day three now.
I wouldn't take buprenorphine in this situation because (a) it will be difficult to get given your situation and on short notice and (b) you're best of getting back on methadone and stabilizing at your lower dose before trying to get off.
So sorry you have to go through with this. Fucking sucks.
There is one other option you have in terms of accessible meds: DXM. It will render you entirely useless in terms of an ability to engage in analytical thought or socialize, but if it's all you have it's worth doing. It can reverse the majority of the symptoms of acute withdrawal at 1-2nd plateau doses. It can be very unsettling, but the relief it can provide when in bad withdrawal is so profound I'm yet to meet someone who took it during acute withdrawal who wasn't able to tolerate its psychological side effects.
That said, DXM is serious shit. You WILL NOT be able to act normal on it, and trying too hard will just make you feel even worse. But if you're able to seclude yourself for four to eight hours after dosing DXM it should be manageable. I wouldn't recommend taking this if you have to do a lot of stuff with family though. In that case it would be better to just go the prescription med route and let them know you're sick (whether you frame it as the flu or what you're actually going through, you know what will work best with them).
Hopefully your family is understanding given the shit nature of this whole thing. If you have no obligations than to just isolate with movies and music in bed, DXM is a viable option if you have the money for it (low cost/day for two good doses you'll probably need to keep most of the withdrawal at bay).
Well, there is also loperamide, which I've heard good things from people using when they need to make up for missed doses on methadone. It's certainly not safer than DXM, but I prefer DXM to high dose loperamide (high dose meaning 80-150mg - and don't kid yourself, regular doses like that will be uncomfortable in side effects, at least if not more dangerous than DXM, certainly more dangerous than 1st plateau DXM doses, and you could inadvertently increase your tolerance to opioids which would suck when you try to get back on your normal dose of opioids).
I wouldn't advice combining methadone and DXM, but you could take your methadone in the morning and take the DXM as soon as it wears off. Definitely do not combine methadone and loperamide. You can safely combine methadone with the comfort meds I mentioned, though the gabapentin will probably overpower it and you'll need to be extra careful about blood pressure when combining it with diazepam and clonidine.
Next to iboga/ibogaine though, I've never come across anything that helps opioid withdrawal (including methadone withdrawal) as profoundly as DXM can. You'll need to play around with the dose a bit, especially if you're not already familiar with the substance. I wouldn't start out taking more than 150mg or so until you know how the substance will affect you. You'll likely need about twice that though, and probably twice a day (so say around 9am and again around 6pm).
Keep your head up. Like you said, you've got options and at least you've got somewhere safe to stay. You don't need this shit though, it's not doing your recovery any favors. The only silver lining perhaps is that (a) it gives you a taste of what withdrawal from methadone can be like under less than ideal conditions and (b) when you are able to get back on your normal dose at least that should be more effective than it was before this sort of enforced sort of detox.
Try to keep yourself hydrated and well nourished. That helps more than you might imagine. Or at least, you'll feel a lot worse if you aren't getting hydration or eating enough. If you can manage to get yourself out of bed to take a hot bath or shower, that really helps, especially at night. I'd suggest watching more upbeat or funny movies, or whatever warms your heart, and listening to a lot of good music. Especially music, it can really help the mood. And if you are able to find comfort meds or do the DXM thing, I'd definitely encourage you to spend some time outside, go for a walk, sit in the sun, that stuff can help a lot too.
Can you get more gabapentin (I'd probably need to take about 4000mg twice a day in your situation, but we're all different), diazepam/clonazepam and clonidine?
How long have you been on the split 25mg dose now, before this shit fest happened? When you get home, it would probably be a good idea to try the 25mg dose again and see how you feel. If it isn't enough, go up a little on your dose and stabilize on that before continuing to try tapering. And don't taper more than 1mg/week if you've been having a hard time with that. How much were you tapering before, more than 1mg/week?
And whether you do it now in order to try and get guest dosing on an emergency basis or just wait until you get home, definitely let your counselor know about this unfortunate course of events. I don't know what methadone prescribing policies in Minnesota are like, but they're pretty good from what I hear. So at least you will stand a change of getting guest dosing approved if your home clinic is onboard with it and supportive. You'll probably need to wait another 24hrs to get guest dosing arranged though.
