I am 22. for a year i've felt consistently tired, regular amounts of food don't fill me up, and i need to urinate often. are these symptoms connected?

Probably: A full history, physical, and some labs including cbc, thyroid check, and chemical profile are in order and perhaps a test of you. Be sure you're checked for diabetes and renal medullary disease (maximum urine sg). I can think of a few dozen possibilities, and even a difficult living environment or having to learn new living skills (you're still young and not yet finished!) can do this.