I just wanted to say hello, welcome, and I'm really sorry to hear about your situation.
I don't feel like I'm the right person to give you any advice as I've not been through the same thing, but I've been suffering from depression and I also find it really hard at work (I'm at work now!).
I know people always say this and it doesn't make it any easier, but it might be a good idea to cut ties with your ex-partner. From what you've said, it sounds like there are too many memories there, both good and bad, to hold onto.
Anyway, I just really wanted to let you know that people are listening in this really difficult time for you. It is so difficult sometimes to admit that we're lost and alone because people just expect us, as "adults", to keep it together when we just feel ready to shatter any moment.
If you'd like to share more with us, please feel free to do so here.
My best wishes