Your symptoms in the presence of carbs are atypical but every once in a while someone seems to suffer the way you are.
If I were you I would measure my blood glucose first thing in the morning and throughout the day. If it is really low then I would stop taking IGF-1 LR3.
likkayouth sent me a study "Insulin Autoimmune Syndrome Possibly Caused by Alpha Lipoic Acid" which probably doesn't directly apply to you but one aspect might.
Insulin Autoimmune Syndrome is a rare disease characterized by hypoglycemia and the development of autoantibodies to insulin without prior insulin administration. What I wonder is if some of those that use an altered form of IGF-1 namely IGF-1 LR3, develop antibodies to either IGF-1 LR3 itself, or possibly native IGF-1.
But no matter what the reason IF you can not keep the blood glucose levels up with carbs then you should IMHO stop administering the IGF-1 LR3.
You are going to experience lethargy and fatigue from igf. It's one of the side effects. The only thing I could say is to make sure you have some caffeine throughout the day. I usually have some type of tea throughout the day and no I'm not british. In the end though, you just gotta deal with it like the rest of us.