Type 1 diabetes develops gradually, but the symptoms may seem to come on suddenly. It can take years for the body to deplete its insulin, but as soon as there’s no more insulin in the body, blood glucose levels rise quickly.Symptoms can then rapidly develop, including: 1  Extreme weakness and/or tiredness.ype 1 diabetes is all about insulin—a lack of the hormone insulin. If you have type 1 diabetes, then your body doesn’t produce enough insulin to handle the glucose in your body.