What to do if i know that it has to do with too much insulin in the body, but what are some symptoms?

If you're not : Injecting insulin, then you don't have too much Insulin in your body. Hypoglycemia is a myth, except with cancer, liver or kidney failure, GI surgery etc. What you're experiencing is a return to normal glucose in a body that is overweight and Insulin resistance, and on the road to developing diabetes later in life unless they learn to change their lifestyle and lose weight.