I don't know how to deal with my boyfriend and his depression. I'm falling into the pit with him.
How bad is his depression?
Very bad. I'm very worried that my boyfriend may kill himself if he loses his job.
You should not allow your boyfriend to damage your own mental health. Talk to him and convince him to get professional help. If he refuses, then maybe it is time to consider breaking up with him.
I understand that you are worried but you should have faith in him. It is always important to have faith in someone that you love.
But it's also important to keep your mental health safe too. It won't do either of you any good if you're both depressed. If he really loves you then he would get the help he needs anyway.