Jessica, you can go and have an U/S any time you want, it's just that you have to pay for it if you have more than I think the 2 covered by Medicare.
I paid 125 Dollars for my first U/S and got back 55 from Medicare - but to me it was worth the 70 Dollars to have the peace of mind that everything was going well.
I didn't expect her to do an U/S today cause her secretary had told me they don't have one, but apparently they didn't count the small one as a ' real' ultrasound- and you didn't really see anything that well - but it was just great to see and be told that everything is going well.

My best friend's husband said he wished, women had a window there, so you could see what's going on .. lol