OK, I think you need to take a deep breath (really, just breath), and try to get some perspective. You have NOT fucked up your life, I promise you. You are 19, still considered an adolescent in medical terminology. Honestly, it sounds to me like you have a case of strep throat. The "white stuff" behind your back teeth is either strep goo, or necrotic tissue. In any event, it is harmless and will go away. Hear me, please: nothing you are experiencing is permanent. I know how it is when everything hits you at once and it seems like there is no hope for a normal future, but you have every opportunity to get your life in order so that one day in the not too distant future, you will wake up as a boring-ass 35 year old with a spouse and two kids and a mortgage and all of this will just be a bad memory. Here's the thing that took me way too long to learn: you WILL turn 25, 30, 35, 40, etc. no matter what (short of death, obvs), so wouldn't you rather do some things now to guarantee your happiness when you are a bit older?
Do you have anyone nearby who you feel safe being physically close/affectionate with? I ask this because often-times when one is having a panic attack, a very intense massage (nothing sexual) with lots of deep muscle manipulation can and will bring all those suppressed emotions rolling to the surface and you will find yourself letting it all out, crying, screaming, moaning, etc. and afterward, you will feel a billion times better.
When I was 20, I had a full-on psychotic break at college, ended up taking incompletes in all my courses, going home and working as a donut maker for a year. FF several years and, although I take legally prescribed opiates for a painful chronic nerve condition, I am happy, healthy, and perfectly sane.
Perspective. Your future is NOT decided. You have NOT done permanent damage. You do need a round of anti-b's (which can easily be purchased online and overnighted to you for not much $$ if you are averse to seeing a doctor) to deal with the upper respiratory infection and/or strep.
I'm sorry you are having such a difficult time right now. Nothing stays the same forever, so you will not always feel this way, that I can promise you.