'Breakdown" isn't a term that doctors use anymore. It's possible to become severely depressed without ever being psychotic. It's often the case that persons who finally committed suicide were functioning competently right up until they ended their lives.

Being very depressed and having no emotional support is a dangerous place to be, whatever you want to call it. I would encourage you to see a doctor, preferably one who has attended you in the past when you were very depressed.

As bad as you feel, it certainly can get even worse. Don't wait for that. What you are describing is bad enough. Could you talk a little about what has been going on in your life lately?