Vaginal bleeding some minutes after masturbation (not my period)

Hello I am 22 years old and I never had sex. I started masturbating for the first time about 3 months ago to become more comfortable with my sexuality/naked body (I get very anxious at the thought of being intimate with someone) and also because I felt sexually frustrated. I discovered that I can somewhat easily orgasm and kept doing it 2-5 times a day since I started (except when I am on my period), you can say that I became addicted to this. I only play with my clitoris (I do not penetrate myself) to the point that it can become sore from friction.

5 days ago (about a week and a half after my last period ended), I masturbated and something inside me started to prick but I continued masturbating because I figured that it's normal to hurt yourself when you're masturbating. I believe that about an hour after that, I went to urinate and saw red blood on my toilet paper and I freaked out. I checked and it definitely came from my vagina. I started wiping myself until I got all the blood out and it went from red to dark brown with tiny clumps (old blood?). It wasn't that much of a flow (definitely not period flow), but I don't know where it came from. I think I damaged my reproductive system, probably my cervix or whatever is directly in contact with my clitoris, and I worry that I made myself infertile.

Afterwards, I kept checking if I was still bleeding and it was all clear the following day. The id**t that I am, I went back to my usual routine of masturbation and yesterday the exact same thing happened. Only difference is that I feel slight cramps resembling menstrual cramps and a small pressure inside. No matter how much I whip myself, I get dark brown blood stains.

I don't want to masturbate anymore, I hope it's nothing serious/irreversible. Is this an infection? Can it repair itself or do I need to be prescribed something?