The Other Night I Was Awoken With Severe Cramps In

The other night I was awoken with severe cramps in my calves. This has happened 3-4 times before, but this time my body started sweating profusely and when I got up to use the toilet, I became completely dizzy and disoriented, fell over and was on the floor for several minutes. Any ideas as to the cause and the treatment. It was very scary. Thank you.