I recently had an anal sex 3 days ago. the next morning i had a rectal pain around the bottom rim of the rectum. it's still not getting better after 3 days especially after sitting for a long time. causing discomfort. i realized there was a little bleedi

Rectal pain: It sounds like it may be a rectal fissure which is a tear in the rectal mucous membrane. It should heal up i'm a few more days bit if it doesn't you should have it evaluated.

May be a tear: You may have damaged or torn the anal opening. Sitz baths (soaking your bottom in warm water) and ice packs may help. If you are bleeding, you should see a doctor for this. In the future, make sure you are very relaxed and use plenty of good quality lubricant prior to engaging in anal sex.