My dr doesn't wanna give me an ultrasound till I'm 20 weeks

Ashley
So I just found out that I'm expecting my first baby ! Due in November so it make me over 6 weeks . My dr had told me I can't get an ultrasound till I'm 20 weeks ... But recently I went to emerge due to spot of cramping ! They had done an ultrasound and found the heart beat of the baby and told me everything is fine but that I can't see the ultrasound , I kinda find this crazy as I have my 3d-4d booked at 23 weeks ! Anyone else thinks this isn't normal