What sort of bgs do you have when you feel like this and have you tested for ketones? Though those symptoms don't have to have anything to do with diabetes both high levels and ketones can cause them.
Are you in contact with your diabetic team?
Note that as a T1 you really do need to be able to test for ketones when your bgs are high. (My consultant got a little upset when I told her that I didn't test for ketones and promptly gave me a meter that tests for both ketones and glucose
).