I am considering going on leave due to mental health issues. I have a long history of treatment and PTSD and depression diagnosis. I am unable to function anymore in this position and in my daily life. My questions are:

#1 If my employee manual says I can take leave for 30 days with approval, and my doctor wants me out for 90, what do I do?

#2 Should I give my manager notice ( I was thinking 2 weeks as I don't want to leave them high and dry)? What if he fires me on the spot? Am I protected or would I go to unemployment in that case? How do I protect myself.

#3 Can future employers find out that I was out on mental health leave or do they just find out medical leave?

#4 Do I have to disclose this is a mental health issue when giving my notice?

#5 I am currently in night school, will I be able to continue school or will this affect my claim?

Thank you.