The pic attached shows my last period and my next period. I didn't chart all the times we had sex but I know for sure we had sex during my fertile window. Friday the 13th I started having headaches and feeling kind of nauseous and lightheaded. I also started what I think is spotting because it's not enough to even fill a whole tampon for 1 day and it's dark brown. From experienced people, what do y'all think?!