Hi dear user, thanks for your query. As per your history, you missed your pills some times, got your period late, having sharp pain and dizziness. In my opinion, I will like to rule out some early pregnancy or ectopic pregnancy( pregnancy outside uterine cavity). Pregnancy test can be negative or faintly positive in these two cases. I used to advise serum beta HCG levels with a repeat level after 48 hrs and a TVS(transvaginal scan) to rule out these. Hope this helps.