anxiety has kicked in

So tomorrow is the big ultrasound day.  I've been fine and dandy about this pregnancy this entire time.  But now I'm afraid that something is going to be wrong tomorrow.  That they're not going to see anything and that the only thing causing my early pg symptoms as well as keeping af at bay, is the progesterone I'm taking.  I know I shouldn't worry.  I know deep down that things will be just fine.  But geesh this anxiety is kicking in hard and scaring the shit out of me.  Oh please let things be OK and let me see my baby developing the way she (wishful thinking) should be.