Bleeding between periods

Has anyone else gone through this? This is about the 5th month in the past year this has happened to me. I keep slowly bleeding between periods.(I'm on the pill so my periods are regular) Its not there all day but usually once a day after I pee there's a small amount of blood.

I went to the doctor a few months ago and he tested my urine to make sure the blood wasn't from that, and then gave me a stronger birth control. All was good for maybe 3 months and now the same problem is happening again.

I dont have cramps or anything and there's no pain, it's just affecting my sex life. It's such a small amount of blood that it never leaks out onto my underwear or anything but I'm still concerned as it doesn't happen every month but just happens whenever it feels like.

I'm seeing the doctor on Saturday but I know he'll probably just refer me to a gyno so I probably wont get answers for a little while so I thought I'd ask on here and see if anyone has gone through it as well.

Thank you ladies!