If you are suicidal you should 100% go admit yourself. I was admitted for suicidal thoughts in 2015. They sedated me with Ativan twice a day so I was calm and set me up with a psychiatrist appt. And they monitor you with a psychiatrist for 72 hours. I don’t think you can lose your job for that it is probably illegal

I've been hospitalized more times than I can count so I'll tell you. if you are under 18, they will need your guardians permission to put you on any medication. if you're over 18, it's your decision.

Talk to someone at work, mental health is included in short term and long-term disability/leave/paid time off and no, legally they can't just fire you for asking for time off for mental health concerns. In fact, it's pretty common in most industries, just not discussed. Inpatient care was a huge step for getting stable for me, I wish I'd admitted myself instead of waiting until I to the point of being suicidal. It'd have saved me a few years of suffering.

If you are in the US, you can qualify for leave through FMLA. Legally can’t be fired or demoted for that. You need a doctor to fill your paperwork for that- a psychiatrist can do so as well. They don’t even need to specifically name the condition or nature of the condition if you don’t want to.