This could certainly inhibit your weight loss if you are not counting the carbs... each cup of decaf coffee has around 1 carb (extra if you have sweetener or cream).

I have one per day with cream, no sweetener, and I have to count 1.2 carbs towards my 20 per day limit.

How does decaf coffee keep you awake? Decaf should not have any effect on your staying awake.

Non-decaf, on the other hand, will also cause an insulin spike much the same as sugar does.

Sorry about the sleep problem, but I'd keep on the doctors until they give you a good explanation.

Good luck
Kim