Possible miscarriage or shedding of my uterus??

Last time i had sex was July 5th and July 9th. I took plan b both times. I had a dr apt on July 30th , took a pregnancy test that was negative and got a depo shot. August i had no period but my appetite was huge. Now I’ve been spotting the past 2 weeks but the last two days i was bleeding excessively. Last night for about an hour my cramps were so bad i wanted to go the ER. It was around 2am. I was in so much pain i was nauseous. This morning i woke up fine but around 3:30 i went to the bathroom and i pulled down my pants and this fell in the toilet. I had a tampon in the whole time and didn’t feel this come out at all. Someone please tell me this is just tissue or something 😔😔 I’m going to see my doctor tomorrow. I tried going to the ER but my deductible was way to expensive. I’ve been crying all day because I’m so scared.