My husband and I are in my second cycle of TTC...I have a very irregular and long period so I used an OPK this month to see when I was ovulating. I should have checked CM too but I didn't understand how until now. Anyways...I'm on 13 dpo and I took a pregnancy test that was negative...is it still possible that I could be pregnant? Im not sure when I should test again because my period is so long I never know when it's coming...I don't have any symptoms really other than I have been nauseous randomly throughout the day and I get stabs of pain in my lower back but I'm not sure if that's related or not. Any and all opinions are appreciated!