Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Call emergency services if you are difficult to wake, faint, have a seizure, develop severe confusion, or have chest pain or a fast or irregular heartbeat.
These signs can occur when hypercalcemia is severely affecting the brain, circulation, or heart, although they can also have other causes.
Seek urgent same-day medical advice if you have a known high calcium level and develop repeated vomiting, worsening dehydration, marked weakness, increasing drowsiness, or new confusion.
Arrange routine medical follow-up if a blood test shows high calcium, even if you feel well.
You should also seek advice if you develop ongoing thirst, frequent urination, constipation, unexplained weakness, or recurrent kidney stones.
Every sign above is quoted from the sofidex article on Hypercalcemia. If you are not sure, err upward — it is always reasonable to be checked.