Agreeing with Alba. There are 5 classic stress points that add up to a bad bout mentally. These are starting a long term relationship, ending a relationship, changing job, moving home and death of a close relative. I feel you are ticking four of the five boxes.
As part of the getting better, you'll need neutral people to talk to, so please ask for this help at your GPs.
In addition I'm sure that many here will, on the basis of your info, feel that you have been badly betrayed and let down. This betrayal will add to your pain.
Counsellors will talk about the stages you can expect to work through, and different schools of thought vary on these, but there's some interesting guidance here
http://en.wikipedia.org/wiki/Grief
I'm concerned that your ex is still able to manipulate you - as you have arranged your work to be nearer this home it might be worth asking her to make arrangements to move out asap.
Best of luck, blessings in abundance and hugs for your recovery from this.