When was the last time you had a full physical? Blood and all that? Sometimes we get so used to the yearly gyn/pap/mammo, that we neglect the general health. My GP is now looking at my vit D as often as anything else. Apparently, vit D levels for most people are inadquate, since we don't get out in the sun much. Simple fix, and there are other things they can check like your thryroid and other hormones. Have heard some amazing stories about the vit D, one right here on our forum.
Are you able to force yourself to get involved in something with the kids, Brownie co-leader, school room helper, something not etched in stone, but that you can chose to get out and do. Do you feel better if you go out to lunch with someone? I usually fight that, since I can get a "fre" lunch at home everyday, but when I do give in and go out, wow, feel kinda better.
Can't always manage this, but often force myself to smile and exchange pleasantries with cashiers, person behind me in line, just see what opportunity there is to make a little chit-chat. Often feel so withdrawn, and it helps a little when I can say to myself, see, that wasn't so bad, you can talk to other people when you want to.
Sun and fresh air are important, take a couple breathers during the day, a short walk, sit on your porch if you have one.
While you have some strength, do what you can.
Could be that the GP will give you an anti-depressant. Run with it !