Fuck those people, they sound like giant oblivious assholes. If someone jokes about you wanting to kill yourself, call it out right then, say plainly, "That's not funny, I have depression," or "Don't talk about suicide like it's a punchline." You don't owe them a smile and you don't owe them the labor of making them comfortable.

If it keeps happening, document it and talk to your manager or HR, or flat-out avoid those coworkers if you can. Take a mental health day if you need one. And most importantly, if any of this is making you actually think about hurting yourself, get help now. If you're in the US call or text 988, text 741741, or go to an emergency room. In the UK call Samaritans at 116 123. If you're elsewhere search for your local suicide crisis line or call emergency services.

You're trying, and that matters. Their comments say more about them than about you. Don't let them gaslight you into silence.