I'm another one who would urge you to keep the appointment. My DS hip dysplasia was picked up 3 months because I kept insisting something wasn't right. It wasn't being picked up without the ultrasound.

Like MummyNaomi said, it might be nothing, but best be sure now. Also, check out that wrapping technique, it could make a big difference. I know it would have helped, if only marginally for DS.

Will be watching to see how you go!