Am I pregnant or not ??

fly

My boyfriend and I had sex in the last day of my period and he came inside 2 days in a row, later on I got my period 6 days earlier (9 dpo) and it only lasted 2 days (it usually be 5 days)

I feel a little bit weird ( sometimes nauseous or a little bit lightheaded) but my breast is not sore

Could it be implantation bleeding or something else?