intense temporary anger/depression? what is this?

i can be fine all day & then like a switch i become super angry in the pit of my stomach, i just want to smash everything and scream. i’m quite a quiet/anxious person so i don’t actually do any of what i want to usually, but i literally could shake with rage like a sort of panic attack. there have been times when i’ve thrown something at someone or self harmed.

as well as the anger i feel deeply sad, like i literally will never be happy again. everything seems fucking awful and i just tell myself that i want to die. i want to shake my family to make them pay attention, i want to tell them how much i want to die (in the moment- i hate saying that the rest of the time bcos i think if i say it it’ll happen)

and then it can pass within like an hour or when i wake up the next morning.

does anyone know if this is normal, or what sort of mental illness label this would fall under? i’ve been depressed before for like a month or so but at those times i feel nothing and just want to lie in bed, this temporary intensity of anger/despair feels very different. i was on anti depressants last year for my anxiety/ocd and my mood was super rational and stable whilst i was on them but ever since coming off them i get like this all the time, it is exhausting and unpredictable. i think it might be worst around my period but honestly can strike at any time, sometimes a reaction to something but often out of nowhere.

i’m literally scared of myself though, i’m 19 and hoping to move out for uni soon. i’m scared i will feel sad and lonely at uni and then feel like this and take a bunch of pills or something. i don’t know.