What Causes Light Periods, Increased Appetite And Headaches After Unprotected Sex?

hi i had sex in april and my boyfriend came inside me. then may,jun,july my periods has been very light . only bled for 1 to 2 day then i missed my period for aug. ive took a few test they came out neg. but im constanly hungry n tired also have headaches. i feel like something is moving in me.