Bleeding after sex?

Hey guys, I've been having some worries lately.

Basically I started having sex 2 weeks ago and done it 4 times in total. The first time I bled which I felt was normal, then I got my period and pretty soon after it ended I started again however the next few times resulted in me bleeding a tiny bit with some brown blood. This might be the remaining period blood.

I have to add that I don't think I was fully aroused which may be a factor. I found it to be a bit painful upon first pénétrating as well until I tell myself to relax.

I'm not using this as a diagnostic of course, but I just want to know if it's something to be concerned of and if anyone else experiences this?