Nicole,
I think a lot of us can relate. I've had anxiety where my heart feels like it's racing and I've even had to pull over to the side of the road until I feel more "calm". This worry can bring on stomach aches (luckily they usually go away).
Having low blood sugars can cause me to be anxious, because feeling shaky, sweaty, irritable, disoriented, etc. can make me "worked up", not to mention other things we have to deal with. If I remember right, haven't you recently been doing tests to be evaluated for tx? That in itself would cause me to be nervous/anxious!
I would suggest talking to the psycologist at the CF Clinic (hopefully yours has one) to start with. This is not uncommon, you are not alone in your feelings and it is very possible that some anti-anxiety or anti-depression type drugs would help.
Also, I'm sure you already do, but deep breathing helps a little when I am starting to feel anxious. Hang in there.