I Am A 29 Yr Old Female. What Could Cause

I am a 29 yr old female. What could cause me to get a instant migraine with nausea, dizziness and sever stomach pain every time I have a full bladder? Then symptoms seem to decrees a little bit after I use the restroom but it normally takes a few hours and lots of rest before I start feeling better. I have had this problem sense I was a young child. I Was told back then that I'm just weird wrong and nothing was wrong with me. No rest were ever done.