I seriously need someone

I posted a couple days ago I was a week late just explaining symptoms stuff like that. Now I need someone to help me figure this out.... I was 13 days late I had unprotected sex with my boyfriend last month and needless to say I expected I was pregnant well I took 2 pregnancy test (not one of the $1 ones) both of them came back negative (I took the test when I was 10 days late) last night (the 13th day) I had severe cramping I felt terrible and I started but not like any period Ive had before big clots and a lot of blood I just thought well it's because I'm late well today I woke up and my pad was basically dry a tad bit of blood and now I'm worried it might be a miscarriage but my pregnancy test was negative. I'm 20 and my friends aren't much help I'm hoping someone older with some experience can help me 😔 sorry I wrote a book