Have no idea what’s going on 🤭

So last night during sex we stopped because i was in pain . Went to the bathroom and when i went to pee there was strings of blood in the toilet. AF went off about 5 days ago so what could this be ? Also hurt when i peed and have been having stomach pains and trouble breathing . I put a tampon in in case i started bleeding alot and i barely see any blood just alot of yellow . Any ideas ?