Go to a local reputable service-oriented fly shop and tell them what is going on. Bring your setup with you and ask them to cast your rod comparitively with some higher-end 2-wts. It could be your casting, the gear, the rod/line interaction, or a combination of all three. Trying a completely different outfit with the help of an experienced fly shop employee will give you enogh clues to figure out which it is. The folks in the shop will probably be able to recommend and sell you what you need - cating lessons, a new line, or a new rod. My guess is it will be a new line or casting lessons.

Good luck,

-John

PS get as close to the fish as you can w/ a 2-wt. I normally don't fish more than 30 feet out with a 2-wt.