I had sexual intercourse while being on depo , but i was bleeding and didn't know it and only had one dose . is it possible i can get pregnant ?

Probably not, but...: One dose of Depo-provera works fine. To maintain effectiveness, one should get follow-up shots every 12 weeks or so. Of course, any fertile couple having sex has the possibility of a surprise baby, so always be ready for marriage and family life. If worried, a home urine pregnancy test gives a reliable result 3 weeks after sex (3 weeks after when conception might have happened).

Yes: Chances are very little but any contraception can fail so you should do pregnancy test