Get off the SSRIs. They will do nothing to help with LSD induced anxiety, paranoia, HPPD or any of that, I don't know this from experience, but I do know that the one treatment option for my HPPD that I would NEVER consider viable was SSRIs/messing with my serotonin system further. Benzodiazepines helped TREMENDOUSLY, the dependency that comes with them is not nice at all though, I would advise against daily use, just take them when you actually feel the anxiety, paranoia, other side-effects you associate with LSD. Personally I had HPPD for 1.5 years and still another year later my vision isn't back to where it was and Depersonalization I had until I got on Clonazepam at the 0.5 year mark. This was caused by LSD and I never believed I would get better. But I mostly did. I never believed I could use drugs that are particularly taxing on mental health again, but I became a Mephedrone addict for over a year and managed to stay mostly sane even with incredibly low neurotransmitter levels and sleep deprivation. Weed still gives me very strong visuals ever since LSD, but I've managed to incorporate these into my expectations of Cannabis, so I avoid it early in the day, wait until the evening when I can enjoy the visuals (to some extent...any visual disturbances do still give me tingles on my cheeks, which is the way my anxiety tends to manifest physically).
OK, that was a lot of information, lol. Basically, I got better, and so will you. You just need time, and a HEALTHY lifestyle. Quit weed for a while, and all drugs, exercise, sleep regularly, eat well, the basics to be a healthy person. Get off SSRIs, but stay on the benzos if you feel you NEED to. After a month or two off the weed I'm sure you'll be able to smoke it at least occasionally again. You're 17...So Cannabis still feels pretty important to you, I've been there...But believe me, Cannabis is nice, but it's not everything, and I think you'll gain a great deal of perspective if you can take a full month or two off it, plus your tolerance will go down and you'll get REALLY baked!