I havent been on my period in 3 to 4 months , i had unprotected sex 8 days ago , how can i tell if i am pregnant or not ?

Since libido increases as ovulation approaches, the chance of a pregnancy is probably higher than one would think. While there is an outside possibility that a pregnancy test would already be turning positive in the next day or so, it could be another week before it became detectable, and about two weeks before you could be confidant in a negative test.