Plus period or pregnant

I'm plus size, about 260lb with PCOS so I have always had irregular periods. This year (2017) though so far I've only had 4 days here and there of very light spotting not requiring even a liner in my panties. I have never gone more than every other month without aunt flo.

I've been checking just as a precaution if I'm pregnant but every test has been negative. I just finished a 10 day round of Provera to try and get it to come but still nothing but cramping.

Has anyone else had Provera and nothing or possible pregnancy when tests said no for months?

Just looking for a little info from the community because my doctor didn't seem concerned.

Thank you!!!