Ruchie, I agree with Alicia. The psychiatrist should start you out on a very low dose of a med and then at follow up visits, he will ask you how you're doing. If he feels like you need more (and many times you do because they start you on a low dose to get your body used to it and then they need to increase it). But if he asks how you're feeling and you are feeling overmediciated (too sleepy, tired or wuzzy), then just tell him you don't feel you can tolerate a higher dose.
You should never feel like you have to take more than you feel comfortable taking. And you can always TRY a higher dose and if you feel like it's too much, you can reduce it (gradually, with the help of your doctor.)
You can do this! You just have to take an active role in your health care. And it's important to find someone you can trust.