I am only 20 yrs old.. now days i can't seem to rememebr anythng..what i study.. i can't remember?

I can't remember where i put my things... when someone tell me to tell someone something.. i seems to forget to tell them.. if ihave a test.. i sudy well but when i go to take a test.. i seems to forget everything i learned...help me pls.... is this some kind of disease?