Frequent urination and abdominal pain can be anything from a uti to symptoms of early menapause. I don't think you are pregnant, but if you want to be sure, take a test.
It sounds like it could be a UTI (urinary tract infection). does it hurt or burn or do you feel pressure when you urinate? If so, this is probably what you have. They are very common. The doctor will want a urine specimen and will prescribe antibiotics.