Overdose symptoms include diahrrea, thirst, loss of appetite, need to urinate more and extreme tiredness. More advanced overload symptoms can include bone and muscle pain, an irregular heartbeat and itching. You can learn more if you click here and scroll down to 'side effects'.
Nausea, vomiting, poor appetite, increased thirst, frequent urination, muscle weakness/twitches and bone pain etc are common symptoms of high calcium levels in blood. For details, visit hypercalcemia.