Mum's know - I was worried about my DSs physical development from about 3 months, at 5 months I took him to see a paed and after xrays and investigations we discovered he was low toned and had hip dysplasia. Now he has had physiotherapy and wore a hip brace for 6 months and is a perfectly healthy 3.5yo.

If your instincts are alerting you to something, get it checked out asap, as early intervention in mental/physical development issues is often crucial to sorting things out/ or getting ongoing support