Hey, welcome back again! So--finally, here's my answer.
I think you should try some calcium supplements. Women need about 1000mg to 1500mg of elemental calcium per day. That's more calcium than most people eat every day. And if you are taking magnesium supplements, it may affect your level. Calcium and magnesium need to be taken together. Some calcium you would get in food if you eat alot of green leafy vegetables and milk products. But since you are having muscles cramps/spasms, chances are you are not getting enough.
Make sure to read the label for the amount of elemental calcium, not counting whatever the calcium is bound to (carbonate, lactate, gluconate, whatever). It should tell you the mg. amount of just calcium, then choose from there. It may matter to you how many pills you have to take in a day. Continue the magnesium with it at the same dose you are currently taking.
Vitamin D deficiency can also cause muscles spasms, cramps. Usually people get plenty of vitamin D by eating fortified foods (milk, bread, cereals, etc) and by spending some time out in the sun. With all the hype about how "bad" the sun is on your skin, however, there are more and more cases of Vit D deficiency all the time. At least 10 minutes of sunshine (even on a cloudy day) on bare skin will give you all the Vit D you need along with your well-balanced diet.
Potassium can help also. But this is better to eat in foods than it is to take supplements. It's easy to get enough with fresh fruit and vegetables. The highest sources (commonly eaten) are potatoes, tomatoes, bananas and citrus juices.
Keep in mind that the Valium may make you feel better initially, but then cause worse spasming later.
Also, with all this supplementation, remember to drink plenty of fluids. Many people live with a mild dehydration that can also cause imbalances that affect your muslces. You need to drink at least 1.5 to 2 quarts a day, half of that being plain water. Avoid soda pop, caffeine drinks and especially colas. (once in awhile is fine, but not as a daily fluid choice).
Give this a good try. If this does not relieve your spasms, you should see your doctor and have some blood work done to see what could be going on.
Ask your doctor to check for deficiencies in Vit D, B12, calcium, magnesium and potassium. Make sure to have your thyroid levels checked. Sometimes muscles spasms can be a sign of thyroid or parathyroid disorders.
Other causes might be pinched nerves, poor circulation, use of tobacco or alcohol, sensitivity to some chemical you are being exposed to, or changing hormone levels.
I wish you well.