Depression/Anxiety from Methamphetamine?

I am REALLY scared. So just answer this without any rude statements, lectures or anything else that side tracks away from my question. If one has used methamphetamine for about 2 months, after going through 2 awful depressions in there life, having horrible anxiety and worries about too many things, then how would they ever rebuild there serotonin? I know it is possible through certain anti-depressants, I took Citalopram (celexa) for 9 months, because my life was so badly overwhelmed and it made me very irritable and easily frustrated, and I had a few break-downs. Well, a couple months ago, I started smoking meth. Ive smoked 35 bucks worth of meth (over 2 months) and have done ecstasy 3 times, the first time, no noticeable effects, the second time, so happy and euphoric and exiting I wish it had never stopped, the third time, took 3 all at once, and one of them did not taste like MDMA at all, so who knows what it could have been, but I popped it (stupid, I know) it was my first rave, and I never went again because when I got home, not only was I in trouble, but I went to take a hot bath (after sleeping in the cold all night long after the rave, bunching together with my friends just to get some heat) and in the bathtub, without even slightly knowing it was going to happen, not expecting it one bit, I wake up and the bathtub that has a hell of a lot of gl crumbs and shards but i didnt get cut, and my mom was yelling my name outside, saying I ped out in the tub. I couldn't even see her, just heard her voice outside through the window that had a broom-stick reaching through, which was obviously used in breaking it. I get out of the tub, clean up all the gl, and unlock the door with my mom acting like someone had died (or almost died, like in this case) The outside of the door had a lot of dent marks near the handle, and my mom said that I ped out so hard that she yelled and screamed (my mom screams very loud) for a while to wake me up, then took a hammer to the door very many times to either open it, or produce enough sound to wake me up, (neither worked) and then came the window, which still isnt fixed after a year. I was out for 15 min. To continue on the subject of serotonin, I can also say that I have been high on cocaine 3 times, all in one day, and it was the only time i did it. I have also used A LOT of Oxycontin ( if I were to estimate, it would be about 2000 milligrams worth total) but somehow never hooked. And then, after I get out of rehab (though not addicted to anything, except potentially weed, which I have smoked nearly on a daily basis for 2 years prior to all these other drugs I have listed) But I then had tried benzodiazepines (Diazepam) up to maybe ten pills cuz it was boring. And then some morphine, which I only did a few times. And then I tried other opiates just once or twice (like hydrocodone or somethin) And to conclude my very well estimated measurements of my past drug abuse, I have had a lot to drink. Im not exactly in the mood for adding up any numbers, but lets just say, I drank maybe once a week until totally wasted for like 2 months. And now, I have escalated to crystal meth. Mostly all of these drugs were taken after my prescription for antidepressants, except pot, cuz its pretty damn mild drug, didnt have anything to worry about. SO for this being a long story/question thing, to inform you on my status up to this day, I would just like someone to tell me why I feel so damn numbed, it takes something extremely funny to make me laugh, Its very hard to focus on my online schooling, and things just dont feel the same. Dont tell me, cuz i already know most of it is due to potentially low serotonin or dopamine levels, maybe even killed brain-cells. I have heard rumors by other patients in rehab, who made fun of this dude for being real dumb/stupid, and a the word perma-fried came up. Can someones brain actually be permanently fried? I obviously do not abuse drugs chronically, but being exposed to depression, and badly, prior to the drugs, has to be like extremely bad right? there has to be something one of you can tell me. why do i feel the way i do now-a-days? and am i bound to have depression for a long time? i flushed the rest of the meth, and am not touching that stuff ever again. where do i go from here? what can i do to rebuild lost lnChl and be happier, and not worry about the future and have anxiety and regret for the really bad things i have done in my life? I REALLY APOLOGIZE FOR THIS BEING SO LONG, but what could anyone work with if I didnt include all the detail? SO PLEASE, I really need people here to answer this and help me, ur going to be making a teenagers life a lot better by helping me with this prob