Aw hon, if it is a core strength issue my chiro told me a great thing to do for babies core strength is to hold them on a fit ball and gently roll the fit ball front to back and side to side and bub will be using their core muscles to stay on the ball (with your gentle assistance to hold them on there). I really hope it's nothing too serious. I'm sure you're just being a concerned mumma and it'll all be ok

On a separate note did you get me pm yesterday?