I've had cramps in my calves at night before - when I was distance running and usually upped my bananas to ensure I was getting enough magnesium which did the job.
For the last week I've been woken up during the night with really painful cramps - had them in both my left and right calves. I had read they were common but they're just so surprisngly painful.
I'm now eating 4 bananas a day
but nothing is touching them. Anyone got any advice? I'd be so grateful if there's anything I can try. This am I was rolling around (happily in a hotel with work so I have a whole space to myself to roll around in) flailing madly til it passed which must have taken a few minutes.
Also doesn't bode well for my plan to try for a natural birth and use breathing to manage the pain - I think I need to some more practice... 
I'm only 24 weeks now so hoping I can find a way to prevent/reduce them.
Thank you.