Helppp

I took 4 pregnancy tests 3 came out positive and 1 came out negative but I’ve been bleeding so I went to the hospital to get checked out and they did blood work and it looks like I’m not pregnant but they want me to come back in 2 days to get more blood work done because they aren’t 100% that I’m not pregnant. Has this happened to anyone I’m just hoping that I am pregnant and nothing is wrong but now I’m worried that I’m not pregnant at all could I have had a miscarriage?