Partner is Depressed/Breakdown

My partner had a breakdown a couple of days ago. She expressed that she felt unmotivated and couldn't make herself do work for months. She said she's been, what I now believe to be signs of depression, having insomnia, lack of motivation and appetite, loss of drive/desire, feels of unworth and loss of energy. She told me she was keeping this hidden from me out of fear, that she was scared she'd loose me if she lost her job. She said she is scared of losing her job, having fallen very behind over the past few months. She says she's ashamed of herself and tried to overcome these feelings for a long time on her own.

I feel terrible for having not noticed these signs earlier. I assumed it was work being busy and she was stressed so not eating or having a messed up sleep schedule was just normal. I didn't think anything of it, and I didnt notice that she was sad or unhappy. She doesn't know if she wants to stay with her job or wait for the "other shoe to drop" and hope to get fired so she won't have deal with it anymore.

When she broke down, I didn't know what to do. I've never experienced anything like this with anyone before. I sat there and listened. I told her it's okay, everytime she apologized to me for how she felt. I told her that we'll figure this out together; if she loses her job, we'll figure it out.

Since then, I've read up on depression and how to be a support for her. I've saved hotline phone numbers. She went ahead and scheduled her own counseling appointment.

I feel like we are without support, isolated, only having each other. Our family and friends live miles and miles away, and we don't speak with them often. We work jobs that don't give way to socializing, and we definitely haven't done that for ourselves over the past couple of years.

I don't know what else to do. I don't know what to do for myself.