Worried

I had a baby on May 27 2016. Me and my husband have been trying to have another one. We had sex on June 29th, had a blood test done the came back negative. Well before I found out I wasn't we slept together again on July 31. Well I started bleeding (dark brown) in August 8th-the 11th. I ended up taking a test on August 19 and it was faint but positive. So I took another on the 20th and that one was positive to.. we slept together almost everyday after my period. Then on the 20-22 I had really light bleeding. So I don't know what's going on. Can anyone help me