"Calm" Magnesium w/ Calcium side effects..? - calcium side effects

I have just begun to take, "the head" with calcium Magnsium last week. It really helps to relax muscles and slept very much faster than usual. However, I tend to wake and sleep in the middle of the night again for 30 minutes to an hour each time. Has it happened to someone? Is this something that can be blamed on the product? In general, this problem has not.