The first signs of hypomagnesemia are anorexia, nausea, vomiting, lethargy, weakness, personality change, tetany.
These are clinical manifestations of the hypomagnesemia.
If you're experiencing those symptoms you should see a doctor to get tested for the hypomagnesemia.
Other signs of hypomagnesemia are spontaneous carpopedal spasm, hyperreflexia), and tremor and muscle fasciculations.
If you do have low levels of magnesium you really need to see a doctor to get treated because low levels of magnesium can be dangerous and cause many health issues.
When you have low levels of magnesium it can weaken your bones, give you bad headaches, make you feel nervous, and even cause you to have heart problems.