Chances of pregnancy

What would my chances of pregnancy be? I am 19 years young. I was diagnosed with PCOS when I as about 16ish and was put on metformin and bc pills. Not good at taking pills so I stopped metformin. Not until recently, probably the past 3 months have I started getting my periods without my pills. My boyfriend and I have unprotected sex frequently. I was due for my period about 4 days ago. I had some light bleeding for about 2 days and thought it was my period starting up but it hasn't come yet and I'm not bleeding anymore. I took a test and it was negative. Was this probably a fluke and I need to take another test, or wait a couple more days for my period?