I'm glad to hear that running is a positive help in what must be a pretty tough time of your life. I was training for my first marathon a few years back when my marriage hit the rocks, culminating in final separation a few weeks before the race. Needless to say I was devestated and my heart wasn't in my running, but i'd get out there as much as possible and plough through it, more as a distraction than anything else. I lost weight (too much, I was already a healthy weight) from not eating well and I struggled to get a good night's sleep for months, but over time it passed.
During the marathon though I was feeling pretty low generally, but used the preparation for the race as a way to focus on something that was just about me, not about my ex or our relationship. I'd heard a quote from Dean Karnazes (spelling?) which I think was taken in turn from Martin Luther King, that went along the lines of "if you can't run you walk, if you can't walk you crawl, but keep moving forwards" (I'm paraphrasing). I knew at the start line that I was not prepared well enough for the race, but I was determined to finish come what may, so when the wheels fell off around mile 18-19 I had the thought with me "run, walk or crawl, i'm going to cross that line". And I did. And it felt like a massive release, and I laughed out loud to myself. It felt like a lot of tension lifting. It certainly wasn't the end of my low period but for a while gave me a real sense of achievement and relief.
I've dipped in and out of running since, and only the last 3-4 months have developed some consistency in my training. I'm in a happy relationship again now, but enjoy the solitude of running by myself, and the enjoyment of having something that's just for me.
Running on it's own won't make you feel like the old you, but it will contribute towards creating a healthy new you 
