Please help!

I was just having sex with my boyfriend and I went down on him as he came and spat in the basin. I noticed there was blood I'm the cum and he said it wasn't from him. I check myself and it looks like I'm bleeding inside.

I'm on my 21st day of my cycle and we had sex last week Thursday. I'm on the pill and I take it pretty religiously but I forgot to take it on Saturday night so I doubled up last night.

Please i need help. I don't know if it's just a scratch inside or something but I'm 17. I'm so responsible with this stuff and I can't be pregnant. Please can someone suggest what this may be

I do have a pregnancy test that I can take but I'd rather do that in a week or so since I can't get another one.