Depressed or Growing up?

idk if im depressed or something but i tend to look mad or sad alot so ive heard. But really I'm calm. & I'm very sarcastic & sometimes unenthusiastic. But thats just how I am. Yes somedays I am enthusiastic & dial it down on the sarcasm & i am happy but on most days im just mad & i snap a lot but i dont know why. I dont mean to be.  Little things annoy me. Someone tell me if its just me growing up or i need help. P.S idk if this will help but ive had my period for 2 years now.