baby movement!!

So I am 18 weeks today. This is baby #3 for me. My last two pregnancies were very rough and I ended up having an ultrasound about once every couple weeks to make sure baby was ok.  However this pregnancy has been awesome. No sickness, hardly any cramping, feeling pretty good. Because I have been doing so well I still have yet to have an ultra sound no matter what I have begged the dr. I remember feeling baby movements much earlier with my second baby. Like at 13 weeks. I haven't felt anything with this baby/ nothing at all!! Baby heart beat sounds good when they do the Doppler but I have a feeling like something may be wrong with baby or something. Am I just being paranoid? Anyone else feeling anxious? Don't have my 20 week appt for another three weeks and I'm so afraid of receiving information that baby may have bone or muscle problems!! Any advice to ease a mama over here