Pregnancy? Why no periods? Nauseated.

Hi doctor, I have pcos,and observed no natural periods since 8 or 9 months, periods only come with meprate having it 1bdx5 days. Had unprotected relation 5 months back but had ipill and got withdrawal bleeding then and also upt negative. Then again 2 months back had ipill, got withdrawal bleeding but not proper only lasted 2 days (usually lasts 5 days), also tested upt negative. Then 1 month back, again had meprate and got bleeding but not proper again lasted 2 days approx and was very light. (usually lasts 5 days). Hence, again tested upt negative. Now, i am having Feeling nausea since 9 days, so did upt 5 days back, negative again (after 2 months of relation). Is the nausea and a little bit of stomach pain due to pregnancy? Should i be worried for a pregnancy? Why isn't my periods coming? This month no periods again. Leukorria history, excessive white discharge is there now. Got hormones checked 8 months back: progesterone very low, LH high, thyroid & prolactin.