Is it bad for you to bottle up emotions for a long time?

i never let anyone know whats on my mind. i just brush things aside. i dont tell anyone really anything about my life and have been diagnosed with depression and anxiety. on top pf that i am bulimic. i feel like not letting anything out is eating me on the inside and i dont know what to do. people refer to me as a "stonecold" person because of the look on my face. apparently i always look angry but i cant help it.