Lately ive been extremely depressed and tired. Is there a food or something i could do to make me feel better?

Im a senior, about to graduate. i should be happy and excited but all i feel is gloom and tired. I catch myself being in awful moods not wanting to cooperate with anyone or do anything at all, i woe at having to walk to the bathroom. And i know that a part of that is me being lazy, but im not usually so solemn. Ive heard that a lack of vitamin B may be related, but what other vitamins or activities would help me cheer up and feel like not poop?