I C of the bladder I have it and that is how I feel every time I have sex and especially when I have an orgasm.
I've heard of people having headaches or sometimes abdominal distress after sex, but never heard anything quite that bad. Really, the best advice IS 'See your Dr." - I feel that's the only way you can get to the bottom of this. Can you move up your appointment to an earlier date? If after some tests, etc., no conclusion is reached, see a specialist, maybe start w/ a Gynecologist, but along the way you may need to see a Neurologist or some other specialist if the Gyne can't help. Good luck, hope you find a cure - that definitely sounds pretty awful...