MDMA and Meth.
I never abused either massively. MDMA I took every 3 - 4 weeks for a 2 year period, meth I would go through a cycle of random use, ramp it up to regular abuse then stop for a few weeks over the course of 14 months or so. I think the biggest issue was that I often combined the two in liberal quantities, which is supposed to compound the damage of both. I'd start the night with meth, and keep redosing through the night, start on the pills an hour or two later, come down after going through a 5 pack of pills and keep smoking meth into the following afternoon.
About 6 months before I stopped using I started experiencing anxiety, depression, panic attacks. At first I didn't connect it to my drug use, but eventually it got too bad to ignore. Right towards the end of my use I had a major panic attack and pretty much withdraw from society entirely, got hit with massive depersonalization/dissociation which is still lingering to some extent. My memory doesn't feel as good as it used to be, my thoughts feel very jumbled and disconnected and I fluctuate through phases of really bad depression. Anyone who's experienced depersonalization knows how hard it is to describe, so I won't try, but 6 months later and I still can't shake it off entirely. I also have trouble trying to distinguish how much of my symptoms is damage from the drugs, and how much of it is anxiety about damage from the drugs (anxiety caused by the drugs). It's a really bad cycle that constantly perpetuates itself.
I feel depressed pretty constantly, though I keep up a good facade for the sake of the people around me. I just really don't enjoy things that much, I keep up with my old hobbies and past times more because they pass the time than because I get any real joy out of them, and have a lot of trouble concentrating. I find it really hard to stick to one task for more than 20 minutes or so before my mind wanders or blanks and I have to go do something else.
Occasionally get really bad periods of depression, just a day or two when I feel absolutely dreadful, sink into a really black mood and feel empty inside. It's all I can do to just crawl in bed and blank my mind until it passes, or sometimes drinking or taking codeine helps ease it a little.
I have improved a lot though, though I still get random panic attacks I can usually ride them out, and I'm at the point where I can leave the house and talk to people without breaking down. I can usually avoid major dissociation moments, though it lingers and strikes me at odd times. Likewise I get really intense cravings for meth every now and them. Not as often as I used to, but every few weeks I'll go through a day or two where I can't stop thinking about it, the taste, the smell, the feeling of that first toke, the burning in your nose after a big line, I'll start tapping my foot and grinding my teeth and my brain screams for a hit.
Mostly I just ride it out on the hope that things will improve. And they do feel better than they did 6 months ago, and people have commented that I seem a lot happier and less withdrawn. I'm hoping with enough time and patience I'll eventually make it back to my old self, that hope is all I have really.