4 years

I have been trying since 16 when I found out I had pcos. I am now almost 20 and had a "miscarriage" in auguest of 2015. I haven't had my period since November 29th 2015 and it's now March 1st, every test including blood has come back negative for pregnancy. I have a drs appointment on the 25th or March, but I'm getting frustrated, I've never missed a period for 3+ months even with pcos. Any ideas on what's wrong??