Scared to miscarry

I've already had two miscarriages but never made it past 6 weeks. I'm pregnant again and I'm now 9 weeks. We had an ultrasound at 6 weeks and we saw and heard the heart beat at a rate of 125. My progesterone levels have been high and I've had non stop morning sickness which my doctor tells me is a good sign. But I'm still so worried! Even though all signs are pointing in the right direction, could I still miscarry? My next ultrasound isn't until I'm 11 weeks