Jenni, are you in counseling? I ask because you've posted about this situation of not seeing the kids you love over your colleague unaccountably ending your friendship and it seems to have hit you very hard. At first, it sounded as if you might be suffering a normal reaction of loss and grief, but maybe it's moved over into depression.
I have had times in my life when normal sorrow morphed into a depressive episode, something that engulfed all my feelings. Could something similar be happening to you?
You might not need long-term-therapy, but some sessions could help you understand this morass of distress you're in and give you some help restarting your social life so the actions or inactions of your colleague and former friend don't hurt you so much. I'm so sorry you're going through this hard time.
I wish you the best of luck.