Sex after pregnancy

So I just have birth to my daughter on July 12th and only had postpartum bleeding for about a week and was able to have sex once after my doctor cleared me to at three weeks. About a week after I had more bleeding for about a week maybe. Just like a period but then it hasn't came back since. I just started having sex again about twice or three times a day for about two weeks now only using withdrawl as well as me exclusively breast feeding. As of about a week ago I started becoming paranoid that I might get pregnant again to quickly since my period hasn't returned back to normal yet. I'm just looking for some reassurance