Okay This Might Be All Over The Place But I

Okay this might be all over the place but I have no idea what s wrong with me. I haven t had my period in about 3 months now. During the 3 months I ve taken several pregnancy tests and they ve all came back negetive. I normally have a pretty regularly cycle but sometimes I can be 2 weeks off but never months. Also, I have noticed the past 2 days that my hair is coming out. Not a lot but like 5 strands at a time. And I ve been having heart burn for a few weeks now. Does anyone know what could be wrong? I know I need to see a doctor but I can t for 2 weeks because I have clinicals for school.
Another thing I ve noticed is that my stomach is kinda bloated. I m not constipated or gases or anything like that.

I m 20 btw.