Hi emsbrat!
You sound exactly like I did when my girls were little. My hubby is a truck driver and gone a lot and I was terrified to drive, so I was home all the time alone with my three girls. One thing that helped me was that I got a double stroller and we were able to walk everywhere. Thankfully at the time we lived in town and had sidewalks (after we moved north to really cold and gravel roads I fell deep into the "hole") When my oldest started kindergarten I had no excuses and since we were all dressed for the weather we would just keep walking after I dropped her off.
I was doing great when my girls were 8,5 and 3, then we moved to another community where I didn't know anyone, had gravel roads, a school bus and extremely cold weather. I suffered for quite a few years until I hit a breaking point and finally got to the doc. I got put on paxil and that has helped with the anxiety so I could go out of the house. I also have a "go-lit" to help with the SAD. I know I should tweak my meds a bit, but at least I'm living and not wanting to jump infront of a logging truck anymore.
Whoops, sorry for going on like that, I'm a tad long winded
So like the other ladies said, get in to see a doctor and get moving and I hope you feel better soon!
Take care,
K