Tripping for 20 hours from LSD/Acid is not a normal thing, peak normally lasts 6-8 hours, with the total trip lasting 9-13 at the longest usually even with incredibly high doses. 20 hour trips are the norm for DOx compounds however, which are commonly misrepresented by both unscrupulous dealers and dealers who simply don't know the difference on blotter and sold off as "Acid", despite being entirely different substances.
They tend to have some uncomfortable bodyload and anxiety and such issues for a lot of people who take them, unlike LSD itself which is usually pretty easygoing and leaves most with a positive afterglow - DOx tend to have more of a hangover and you can feel pretty weird, out of it, and generally frazzled for a few days to a week or two after your experience, depending on the dosage and how tiring the trip was for you physically/mentally.
So yes I wouldn't worry, you'll be fine and these feelings will go away quickly, but it's very unlikely what you had was actual LSD, and I wouldn't let this bad experience rule out the possibility of trying the rather beautiful real deal in the future (however if you're on SSRIs, psychedelics may be best left until you're off them, as like others have said they can react unpredictably and have more side effects or simply be a less enjoyable and intense experience) - but not only that, I would avoid placing much of any trust in the person you purchased this "acid" from as it sounds like either they purposefully sold you another substance under the wrong name, or don't even know what substances they're selling themselves, either of which could have meant something far worse had the substance been something more dangerous like one of the NBOMes dosed too highly etc.
Eat healthy, sleep well, and stay positive and you'll feel completely fine in the next week
Also please be careful with SSRIs, I'd never feel right in telling you to stop taking them if you've been prescribed them, as I'm no doctor, but I can speak from the experience of those in my family and friends who've had their lives severely damaged by SSRI addiction that they're something you really don't want to be on long-term. SSRIs taken for a shorter period like 6-12 months in combination with seeing a good therapist, doing things like cognitive behavioural therapy, and taking steps to use the boost the SSRIs gave you to take control of your life again and do the things you previously couldn't without them (be it getting a job, getting out and making friends, learning better social skills, or learning coping mechanisms for your underlying issues) can be extremely positive and change your life in a wonderful way - but using them simply as a crutch in the long run is a road with only a bad ending. SSRIs cause your brain to adjust by down-regulating your serotonin transporters over time, meaning that if you keep using them for years and years, you'll actually be in a worse off situation serotonin-wise than you were before the SSRIs, and without them you'll feel way worse than before.. and with them you won't feel as good as before either.. leaving you in a big rut. Make use of your time on them to make positive lasting changes to your life and don't aim to stay on them forever if you want best results, just my 2 cents, but again, I'm not trying to substitute for the advice of your doctor (though it's worth noting that doctors are often paid to push SSRIs on people and it's in the interest of them to keep you on them long term since they don't earn a cent if you stop taking them, so bear that in mind
).
Even we can help you here with the issues that resulted in you needing SSRIs, head on over to forums like The Dark Side and you'll find some great support for depression and anxiety. I suffered social anxiety most of my life and managed to cure it myself (with a little help
) and the same can be said for depression, even if one can't cure it, one can learn to make it background noise and live a happy fulfilling life without the need for a pharmacological crutch. Ask away in The Dark Side and you'll get lots of friendly support, the guys and gals over there are some real lovely souls and I promise they'll do their best to help. :D
