Dear Kerrievans,
I agree with horselip. It could be diabetes insipidus. However, my may concern is that you could have recurrent tumor at this point. Please consult your neurosurgeon, or at least your PCP. An MRI may be indicated at this time to rule out regrowth, which could explain your new symptoms.
Sounds like Diabetes insipidus to me. This is caused because your pituitary gland is not making enough Anti-diuretic Hormone. The medication used for this is called Dessmopressin or DDAVP. It is available in a pill form, nasal spray or injection. There are a few other conditions that can mimic this so it is important to get it ruled in or out. I have this and without medication I am also up every half hour drinking and peeing.i rec that you see a neuro endo to rule this out, your other pituitary hormones, and have a current MRI. It may be as simple as taking a little pill every night to help you to hold onto fluids.