Could I be Pregnant?

I was supposed to start my period on Thursday but have yet to start. My husband and I have been TTC for the last 4 months unsuccessfully. I do have PCOS and have been dealing with it since I was 15. We had sex four separate occasions leading up to the day before I supposedly ovulated. I have had cramps, been dizzy, fatigued, and have had a change in appetite. I took a test today and it was negative (I use the HCG strips) could I still possibly be pregnant? Has anyone else ever experienced anything similar and end up pregnant?