scared

I am a 20 year old female who has been experiencing serious symptoms for about 8 months now
It began in September of 2016, I was constantly having to clear my throat of mucus. At the end of my first semester of college I took adderall to study for a test and thats when it went all downhill. After taking it i could feel severe dryness and what felt like acid in my throat. I remember feeling the inside of my throat and feeling a bunch of bumps and having an anxiety attack. Ever since then, I have lost weight (specifically muscle wasting). Whenever I eat even if its dark leafy vegetables it feels like i have acid reflux. My throat is in CONSTANT dry pain with a raw feeling. Now I have pain in my leg muscles as well as severe stiff neck and swollen lymph nodes. I wake up in the morning with one or sometimes both of my arms completely numb. My back often hurts and there seems to be little to no muscle left on my body
I now find it somewhat difficult to take deep breathes and find it more difficult to exercise. I sometimes have stomach pain as well.
I don't know what to do anymore. I am in extreme pain and this causes me constant anxiety for i fear I have cancer or I am dying. I have gone to the doctor and gotten blood tests and an ultra sound which all turned up normal. (doc said all my vitamins looked "excellent" actually). I am young and this is really starting to scare me because I feel like I shouldn't be having these problems. I'm in constant discomfort and have horrible anxiety due to these issues. Let me know what you think as doctors have done little for me.