I think I had a miscarriage.

Hello. So I'm going to get straight to the point. I had sex on the 15th of this month..July, unprotected and my boyfriend and i did the withdrawal method and I didn't think twice about being pregnant. I didn't have any symptoms or anything like that. My last period was July 4th, and then on July 25th one night, when I wiped after peeing there was very little spots of blood on the toilet paper and then i wiped again and it was little tiny spots of blood with a small piece of beige tissue from my vagina like my uterus was shedding and i don't get my next period until the 31st. After the 25th of that happening I havent been spotting or anything like that. So Im trying to figure out did I have a very early miscarriage? I took a pregnancy test today and one line was really dark blue and the other line was very very faint like you couldn't even see it. Can someone explain this to me, and tell me what might be going on? Thank you :)