My (23f) partner (24m) is severely depressed do I leave him?

for context we have been together for five years and basically live together. I don’t know what to do or how to go about this I’m just genuinely so drained and I know when someone is going through something to be there for them but when do you choose your mental health and sanity. For months now he has been drinking heavily and constantly talking about his shitty parents and how he feels like a fuck up and it turns into this big thing where he starts talking about dying and how he blames God. It’s made him very clingy to me constantly calling, wanting my attention where I can’t breathe and have time to myself I expressed I need some space for my mental health and then he breaks down and makes me feel guilty and then I don’t get that said space. I feel like my boundaries aren’t being heard and I’m like his emotional support dog. For example when I said I needed space he started crying and then faked being dizzy and then said he threw up when he didn’t it was literally spit. Like huh?? I don’t even know how to react anymore I’m so like clocked out of it.