What can i do about low blood sugar causing tiredness?

Depends: If you have diabetes and your sugar is low, take less medication. If you don't have diabetes, then you probably don't have true hypoglycemia. What you're experiencing is an elevated post-meal glucose due to your obesity and Insulin resistance. It's a normal response of your body returning your sugar to normal, but it causes symptoms. The cure is diet, exercise and weight loss not eating more.