Heartbeat but not pregnant?

Okay so this is going to be long and I’m sorry but okay so I’m 12 weeks pregnant and have blood work and urine test both positive previously but on Friday I started bleeding. Slight cramping so decided to get in the shower and get out and was getting ready for the day and dropped something and noticed there was blood running down my leg (no clots) so I of course freaked out and called my mom and the babies father(separated) and they both told me to go to ER. At the ER they did a urine and drew blood and while waiting for results did a fetal doppler and found babies heartbeat it was 184 which the two nurses were talking about how high that was but mine was 120 so they thought that might be why. Well they waited like 10-15 minutes and took it again with the doctor in the room. The babies heartbeat was 182ish and mine was like 80. Well my urine came back negative for pregnancy. But there was a heartbeat so doctor did a pelvic exam and said that I looked pregnant. Well then he said that since the pregnancy test came back negative he refused to call in an ultrasound tech and deemed me “not pregnant”. So has anyone ever tested been bleeding during pregnancy and tested negative and it actually be positive? And also how is there a heartbeat but not pregnant? And third question why is the heartbeat so high?