Question about diabetes insipidus?

Is headache and lethargy common with Diabeties Insipidus. My 13 year old daughter was in the ER for 5 hours the other night and the doctor suggested diabetes insipidus, gave her some darvocet for the headache and said to follow up with our primary care for an MRI and confirmation of diagnosis. The doctors office is not open on the weekend and the headache has not gone away. Should I take her back to the ER or is this just another symptom of her possible condition?
I am aware of how the disease works, the question I was asking was about headaches in association with it.