My almost four month baby is 19lb5oz (8.85kgs)?

Hello sir, I just need some advice from other mothers with children older as I think the key issues that are increasingly age appropriate things very quickly that the Jolly Jumper (http://www. Toysrus. Ca / product / index. jsp? ProductID = 2688484), dressed as if style outâ (currently six bags of 18 months grobag) and the main question is who puts on weight so fast that my back / shoulders are killing me (had a bad back to begin with). Lady massage using my elbows to free “my shoulder” and I’m worried about the coming months! weight is 97 th percentile, but it is the height of his head, he is just a big kid like his dad:) Any advice appreciated XPS – It’s four months to 18.