Hi there,
Our wee boy is almost 3, he's been on an insulin pump for about 2 months and is getting on well. prior to this he was on injections for just over 12 month (total nightmare). He can still go quite high if we dont clinically weigh his food or he can also go low for the same reason. Activities, he is a live wire, always has been. The Diabetic Educators should be able to help regarding activities and for swimming, we take the pump off for about 1.5 hours and let him go nuts. Sometime i give him a popper prior to swimming to raise his BG as swimming can bring him down to low otherwise.
Its great for them to see other kiddies with a pump so recommend you tag onto others in similiar situation.
Also, we have just got him some new pump holders, they are stretchy material (like latex i spose). Its a band that goes around his waist (like a cummerbund but not so wide) and the pump fits into a double fold in the material, its really secure and the pump doesn't jump around at all. Best thing ever esecially in a sports environment. We bought it for 30 dollars (in oz just now) but reckon i could make my own with a sewing machine easy enough. He floods his nappies 2-3 times a week as he likes lots of liquids but the pump is never affected. Dont worry about it, they are really robust.
One thing... if you struggle with the control of the pump then dont stop asking hte diabetic educators until you are confident with it.... its their jobs to help.
Best of luck.
RJM