I had anal sex and now i have a feeling of going to the bathroom all the time but when i go nothing comes out?

Doctor can examine: Anuses are not designed for in-out, in-out sex. Just like in a big city, some streets are one-way and some streets are two-way. A vagina is created or evolved to be a two-way street (penis in, baby out). But, the gastrointestinal tract is designed to be one-way, with an opening on each end. Food goes in the mouth, and the brown stuff goes out the butt. Friction and trauma damages anus and rectum.

Decisions to make: The anus is a complex system with muscles & nerve endings that provide special information. It can tell you the difference between liquid/solid/gas that wants to exit. It can tell you if it is time to go or not. As long as you leave it alone to do its job it will do so. Anal sex can/does damage the sensitive nerve endings & muscles. They may heal if you stop. If not, expect to loose function.