Hiii...i'm 24 Year's Girl ..i Had Sex With My Bboyfriend

Hiii...i'm 24 year's girl ..i had sex with my bboyfriend before 3 months ..and i haven't my periods past 3 months ...but i taken my home pragnancy test with prega news ,, first test after 1 month after sex and second was after 2 month but both result were negative.. now i'm taking regostron pills past two days...is it safe ..