2nd Ultrasound - very scared

I just posted almost the same entry under Pregnancy After Loss but I thought I'd write this as a journal entry as well.  I had my second ultrasound yesterday and everything went great. Since I'm high risk, I will be getting ultrasounds frequently.  Anyway, they have some high tech ultrasound machines. We got to see the heat images of the blood pumping through the baby's heart chambers! We also got to hear the 150 beats per minute! It was amazing. They said everything looked great and I'm measured where I need to be (today I'm 7 weeks 4 days). But last night, I started bleeding and it was a medium brown discharge and more than just when I wiped. I've been through this before and know brown blood is old blood and I tried to tell myself it could be from the vaginal ultrasound and hoped it would go away. This morning, it was minimal but then later in the morning it covered my underwear (sorry tmi) and when I wiped it was all there again, still brown in color and I'm also having some cramping - although I can't really distinguish if it's normal pregnancy cramps. I thought it would go away by now. I'm only freaking out because this is how it started last time and ultimately ended in miscarriage weeks later. I'm just praying to God everything is okay. I'm so scared right now:(  On top of all this, today is my Bday!  I thought I'd be celebrating this pregnancy, not freaking out!