The same thing happened to me years ago with paxil. (i'm a pro at switching meds, I'm on my third or fourth at this point.)
I would first and foremost talk to your doc. Then with your pcp's help switch to a differnt med. Ask your doc. to ween off of paxil, while starting a new med..
take 1/2 of your paxil, while starting 1/2 of a new med (effexor, cymbalta, lexapro.. whatever), then down your paxil, while you up your new.
It's typical that meds loose their effectiveness with your body. You can even try upping your paxil.
good luck and let us know how it goes.