I'm currently 13 weeks pregnant and for the past 3 days I've had abdominal pain and pain what feels like in my anus. It hurts more when I pee or try to open my bowels or if I sit down but it's there all the time I don't think I'm constipated thanks

Well, a good place to ask the question is your doctor.

The pressure from an expanding uterus is hitting every organ, muscle, nerve, blood vessel, tendon, ligament, and bone around it.
Each woman is going to have different reactions to her baby growing.
We can't possibly identify what is pressing on what, which is why you need a good relationship with your doctor and the staff, even if you don't always talk to the doctor directly.
Good eating habits, maintaining the right weight, doing the right kind of gentle exercises, getting some walking in every day, sitting right when sitting, and so on, are all part of keeping pain to a minimum.
If your abdominal muscles are weak, for example, they can't hold everything in the places they are supposed to be, and organs sag, get uncomfortable, even fall out!

You need to mention the pain when you talk to your doctor or clinic in case you have a urinary infection.
Or, it could be pinched nerves, because you also feel it at your rectum.

Pelvic tilts are one of the best all-around good things any woman who has cramps, is pregnant, or who is old like me, can do. I do them (lying on my bed) several times a day. We tend to let our back sway in at the bottom and our abdomen stick out, not good for any kind of discomfort.