TO MUCH INFO

So, I was thinking there was a possibility of me being pregnant. My boyfriend and I had spur the moment sex and didn't use a condom. Today is roughly 3-4 weeks since we had sex. & I had a bad stomach ach and went potty. I went to wipe and this is what I found. Any idea!? It was like a sack thing with blood. I'm scared it was a miscarriage.