Walking problems

I took Ryan in to the doctor today because he continues to have more and more problems with walking. He use to walk with his feet inward- which is a very common thing with kids when they first start walking and they usually grow out of it by 3 yrs. But now he is walking (when he does) on his toes or the front of his foot, at times will drag his feet (when he is tired), has now has started to trip more, and his feet are very inward now. He will walk short distances and then wants to be carried because he is tired. RJ and I and others have noticed a big change in the last 2 weeks. He is walking like he did when he very first learned how to walk. When he runs he has to use his arms a lot to keep his balance. He will be seen by physical therapy and I will know more from there, but our Dr. who I trust very much is worried that he is having muscle weakness that could be developing something as serious as muscular dystrophy. I am trying to not drive myself crazy with the what ifs. I haven't even looked anything up. I don't believe he could have MD. If he has to wear braces to fix this I will be more than happy with that if that is all it is. RJ and I have been watching this ever since he was hospitalized a year ago and just have felt something not "right".