Problems after anal?

This may be a TMI story but I just want to get it out of the way since its been eating away a Not my mind. About 2 weeks ago my boyfriend and I tried anal sex for a second time since I started my period and wanted to give it ago again. The first time went really well no pain or tears so we tried it again. I don't know if maybe it's because we tried a different lube or maybe I hadn't quite "prepped" before hand but it was a little more difficult the second time. there was some pain and a very small amount of blood but it went away very quickly. Now to the present I've been having discharge recently from back there. I don't know if I should be concerned or not this hasn't happened before. Should I just go to my doctor to figure it out or should it go away on its own? not sure what to do thought I'd ask!