Lower abdominal pain

So the past couple of days I’ve been having abdominal pains. So bad that I can’t laugh normally or cough too hard. It’s kind of crampy feeling but also a soreness. Not only that, I also feel nauseous and TMI but I also had diarrhea last night. Don’t know why honestly. I used to get these pains when I was in high school but never this bad. I’m currently not on birth control and have been off of it for about a month because I felt that they caused such bad pain in my legs and I thought it might have been blood clots (I was on the pill). I’m engaged and we aren’t ttc but also aren’t avoiding it, so he does finish inside me. we’re 20 y/o. Just wondering what this could be and when to know to go to the hospital/doctor.