PMS or Preggo? Nipple situation! Trying to get Prego with PCOS

I found out a couple months ago that I have PCOS. I never get my period and they don't know when I last ovulated on my own. 

We have visited and infertility doc and they put me on metformin I have been on that for two months. The week of the 2/8-2/12 I was randomly spotting. No idea why. The doc said I could be ovulating. So my husband and I of course have sex everyday. I've also been on a 10 day pimetrium (sp?) cycle which I ended Wednesday.  If I'm pregnant I won't get my period. If I'm not, I'll get my period and then start my ovulation cycle treatment on the third day of my period. Since I never get my period on my own I have been testing all week to see if I'm pregnant.  I keep getting negatives but I'm not sure if it's bc I'm testing to early or bc I'm testing at night. Still no period too. I noticed this week my nipples are randomly hard. I've NEVER had this before. Ive also read that some meds can make the readings wrong/negative. Is metformin one of them? I've had no appetite really, my boobs are def bigger. My nipples hurt. What do u guys think? PMS or Preggo? Help me!! Should I test again tomorrow?