In the past yr i lost 60 lb but now find myself waking up at night very thirsty i am on no meds am gluten corn and dairy free and my joints r stiff?

Possibly diabetes: With the symptoms you describe, you should definitely be tested for diabetes. Also need to consider hyperthyroidism. Weight loss to that extent should always prompt a medical evaluation.

Why a strict diet?: The information you provided is insufficient to give you an educated guess, but you have raised several issues: 1) on what basis did you eliminate corn, gluten, dairy from your diet & what did you hope to gain from doing so? 2) if your weight loss was involuntary what evaluation have you had as to cause? 3) what underlying meds are you taking /diseases you have (autoimmune, diabetes... ).