bleeding and or spotting brown.

My period calendar says I'm 8weeks and three days pregnant however I started spotting two days ago it's been brown in color but not heavy flow I don't have to wear a pad or panty liner or anything like that. I went to the hospital yesterday because I been having mild cramps. They did an ultrasound and could see the baby in the sac and it's in the uterus but they couldn't find a heartbeat. At this point I just left the doctors office where he did an exam and told me my cervix is closed he had bright red blood on his glove after the exam. He said right now I'm to early to tell anything and all we can do is wait this out to see if the eventually find a heartbeat or I miscarry. Idk what to do or think because I don't wanna lose this baby. I need some reassurance I guess from other women who may have been through the same things.