I get those symptoms too. Last winter I CT'd from a daily dose of around 1200-1800 mg (yes, my doses tend to grow quite extreme due to the tolerance building up heavily) because I ran out of supply. I got horrific anxiety and depression, alternated between complete and utter lethargy and complete overstimulation, complete insomnia, diarrhea, vomiting and nausea. Combined with a marked increase in heart rate and BP.
I can give advice regarding my tapers but please don't take this as some kind of medical advice, and we are all different and react differently.
When I've used such high amounts (like now) I usually start the taper from 900 mg. I haven't found any need to start the taper from something like 1500 mg or 1800 mg. 900 mg has always been enough to keep the worst WD at bay and sleep somewhat normally.
Usually, I reduce the dose every 4th day by 150 mg, but for some every 7th day may be needed.
So from 900 mg, it would look like this
900 mg x 4 days
600 mg x 4 days (this step I usually cut the dose by 300 mg, for some it would be better to stay at 750 mg for 4-7 days).
450 mg x 4 days
300 mg x 4 days
150 mg x days (this is where it gets hard, so I sometimes stay at 150 mg for 7 days)
75 mg x 4 days
So this taper would take 24-27 days.
Some people even reduce from 75 mg -> 50 mg -> 25 mg but I have never found a need for that. 75 mg is such a small dose that you really don't get any severe withdrawal at that point anymore.
A more cautious version of my taper schedule is to reduce by increments of 75 mg; 750 mg -> 675mg -> 625 mg -> 575 -> 525 -> 475 -> 425 -> 375 -> 325 -> 275 -> 225 -> 175 -> 125 -> 75 (and from 75 with increments of 25 to 50 and then 25). This would obviously take considerably longer.
There are few remedies for pregablin withdrawal. Benzos alleviate some, but only some, symptoms. And if you do take benzos, take them vary sparingly. As you probably know, they are a completely different ballgame to withdraw from. Gabapentin most probably share a cross tolerance with pregabalin, as both are gabepentinoids with pretty much the same method of action. That's why I would avoid taking gabapentin. There is a study that says there is no cross tolerance between gabapentin and pregabalin (e.g. this study)
https://patents.google.com/patent/EP1196160B1), IME they share a very high degree of cross tolerance. Although gabapentin is both less potent and weaker in just about every aspect, it might be easier to switch to it when you've reached a lower dose of Lyrica and then continue the taper with gabapentin. But I have to admit that trying to switch to gabapentin has failed every time; gabapentin helps somewhat with the insomnia but not for the anxiety and depression.
On another note, I've found Taurine to help quite a bit with the anxiety. It's a (very) weak GABA-A agonist and has a slight sedative effect in high doses. And it's very safe to take it. Other than that, there's not many other drugs that may help. For insomnia, a small dose of mirtazapine (7.5 mg) and a high dose of melatonin (6-10 mg) does also help somewhat for the insomnia. I'm not that familiar with antiemetics for the nausea, but there are certainly some ones (any idea anyone?) out there that helps. Maybe antihistamienes like hydroxyzine. If you have a raised BP or heart rate during withdrawal, a beta blocker like propranolol is helpful.
To be really honest, the thing that has helped the WD's most is alcohol. And that's pretty much the worst thing to start taking regularly. If you have a high degree of self control, taking a few beers every now and then is no big issue though. If you struggle with insomnia, I can't say that you can't take a few beers if the insomnia is really bad. You might get a few hours sleep until the alcohol wears off but that may be better than no sleep at all.
Edit: Squeaky, I tried to PM you but you have chosen not to receive PM's. If you don't mind I'd be glad to send you a message.
Pregabalin withdrawal is hard but perfectly achievable. I've detoxed from benzos 3 times (and has to do a 4th it seems...) and that was in a totally different league, you can't die from Lyrica withdrawal, it's just nasty but it also gets better somewhat quickly in my opinion. There's no PAWS like for benzos that lasts months to years. When WD'ing from pregabalin, you start feeling better within days to weeks. Again, some suffer considerably longer, but at least it may give you some hope that for all it's not the case.