Complete placenta previa?

Luanne
We just had a 21 ultra sound (as a follow up to an 18 week) and I was diagnosed with complete placenta previa. 
The ultrasound doctor didn't seem too alarmed and told us we had to come back in 8 weeks for a follow up, but could resume normal life activity.  However, later that day our midwife called and let us know how serious it is and gave us a list of not to do's to help prevent any bleeding. 
Wondering if anyone else has had complete previa before?
I'm all of a sudden really anxious about my pregnancy, because up until this point things were going so smooth.