Please help--10 weeks blood, no cramping

Please help!
I wiped and found bright red blood.  There was also some in the toilet.  I  am 10 weeks along (heard the heartbeat during an ultrasound at 7 weeks).  I've been having terrible morning sickness (nausea and some vomiting) and my whole abdomen has been tender for the past few weeks (mostly concentrated the upper half).  I haven't had any cramping.
I called my doctor and she wants me to come in tomorrow morning for another ultrasound.  I have no idea how I'm going to get through the night.
Has anyone else experienced this?  What happened?  I'm obviously terrified I'm having a miscarriage.  Any help/advice would be greatly appreciated.