I Have Been On Metformin For About Six Months For

I have been on metformin for about six months for pcos. I went from 2 periods a month (my normal) to No period for going on 3 months. Hpt's are all negative and just got a negative blood test. I'm having pregnancy symptoms so was wondering if it's a rare possibility I could be? We are not trying (also not not trying) so I don't think it's just a mental thing in my case.