Pcos & possibly preggas! Help

Hi, I'm confused and looking for help. I have pcos and take metformin. I have been tracking my periods since feb this year. My cycle has been 38 or 39 days since feb. I was obviously chuffed as I thought I was irregular. My last period was 6th nov so I would have been due on sat/sun. I still haven't come on. I feel sick constantly only break  is when I've just eaten. I am bloated and have lower back pain. Boobs are bigger. I have head aches and peeing more. About a week and a half ago I lost about 4lb for no reason and have put it back on now. I have weird cramp like feeling in my stomach but it's not painful. I have had a negative pregnancy test. ( it was only a pound shop test) but I thought they all measured the same anyway.
​Please help me make sense of this. I have read that pcos can give false neg tests but also the opposite. And I find it strange as I have been regular for over 9 month.