Bleeding at 4 weeks pregnant!

Hello, everyone i would like to say that I need some help here. I had a round of iui done on July 14, so after that my doctor told me to wait until 28th to take a pregnancy test. But I ended up taking it on the 27th and it was positive. But what really got me in a pickle is that I started bleeding on 28th at 2am in the morning. But I'm still testing positive with home test and with bleed test. I would like to know should I be worried and just wait and see what happens? Also the bleeding is not hitting the pad.