I know exactly how this is going to sound but it worked for me while I was pregnant and having leg cramps so bad I'm sure it would have hurt less to chew my own leg off.... but what I did was take my fridge magnets and shove them in a line down my side of the bed underneath the mattress. Space them out, i think I used about 3 or four and I swear, I never had another cramp again after that. It very well may have been coincidence and it sure sounds like an old wives tale but if you're still hurting bad anything is worth a try right? I know you can get those copper / magnetic bracelet things from the pharmacy (at least here in the UK) so maybe it works on the same basis as those?
Hope you find something to help ~hugs~
Numpty:- (num-p-tee) dialect, chiefly Scot, ~n. 1. a bumbling fool: one who is intellectually challenged. 2. widely known in Scotland as an MSP (Member of Scottish Parliament).