Bleeding 4 days after period

[Piggieperson]

Hi. My last period started 2nd May, finished 8th may. I had sex with hubby on 11th (Sunday) and again this morning. Last month we has sex about 3 times, none of it baby making sex, he pulled out. I'm not on any medication or bc. This morning I decided to pleasure myself, had an orgasm. 30 minutes later I go to the toilet, wipe, and to my shock see blood. It's red and thin. This is the first time it's ever happened to me. I had an mc in November, and a late period at the end of March (possibly due to uti and antibiotics). Does anyone know why I could be bleeding today? I don't know if it's spotting or not so far, and I haven't found much about it on the internet