Calcium is the mineral in the body which causes the contraction and magensiunm causes relaxation in the body. Too much calcium and not enough magnesium could be throwing you body way out of balance. Yu need to be taking 400 -800 milligrams of magnesium per day guage it by bowel movement. Loose movement=too much magnesium back off til you find the right dose.
How do you know it is the calcium and not something else you have taken?
Many times magnesium defiiciency which uis very common manifests as anxiety.