Plan B...

Alllllllll right, here's my story. Tuesday night around 10 or 11 pm. Great sex, defective condom... It broke 😱. I had to work and the pharmacy closes before my shift ends. So my boyfriend of 3 years had to get them for me. We live together. But we are seriously young (too young for kids). He got the contraceptive for me, I took it Wednesday night (the last day of my period) after I got home around 11pm. Today (Thursday) I've been nauseous, gassy (tmi) and getting sharp pains where I get period cramps. These are all side effects written on the box. This is my first pregnancy scare in a year and a half of being sexually active.... Guess what. I've had a Pap smear scheduled for this up coming Monday. My first one! I'm terrified and I need some advice on all of the above. I know I have to tell my doctor about taking plan B.  But that's about it. Do I ask for STI checks as well? I know we've both been monogamous.. I am so nervous.. I haven't been to the doctor since I was like 12....