you need to speak to your Dr.
If you are on prescribed medication, it would be unwise, surely, to stop taking them before a Medical.
You also need to be more adult about this and treat your illness responsibly.
Talk to your manager, this should be treated confidentially.
Some of the comments already posted in response to this show why dripdripdrip resorts to an anonymous forum... Ignorance and ill-informed comments which only serve to increase the stigma surrounding mental illnesses.