can i even get pregnant ?

i just wanted some advice or imput and wonder if anyone has had this, i had my first child in august she is 1o mnths old, normal conception no probs, i had normal afs until i got pregnant, since then all my afs are late, we bd'd in may although i was already late at that point, two days after that i had a bleed red blood that lasted an hour or so and stopped was similiar to af bleed but didnt last long like normal, however i counted that as a period and bd'd 12/06 if that was a period it would mean im fertile but who knows, i did a test on the 11/06 and was BFN i dont know when i should really test and if its possi to even concieve?