That title is lame

I am a 42 year old mom of two little boys (7 and 4). I stay at home and we home school (secular, progressive, eclectic).
In my 20's and 30's I was totally into fitness. I was an aerobics instructor, worked with a personal trainer regularly and LOVED every minute of it. I looked awesome, felt great and wouldn't miss a work out for hardly anything because I enjoyed it so much.
Then, my life fell apart. My first husband left me and I had to move, re-invent my life, etc. and my working out fell by the wayside.
In the ten years since, I've never managed to get it back on track. I started to, then got pg with my first son (and moved across the country), got back on track after he was born, and then lost it again when I got pg with my second son (and moved back to CA).
I did OK in CA, and since we moved to VA, I did OK here until about two years ago when I tore my medial collateral ligament in my left knee. That took forever to heal, finally got back to the gym and tore my meniscus in my right knee... got back after that and a few months later had a second/third degree sprain of my right ankle. Came back after that and did it AGAIN, only this time, it was 3rd degree, a totally different injury (so not because the ankle wasn't rehabbed correctly).
Since then, I've not been to the gym regularly at all. I'm totally lacking in motivation, feel like YUCK, and have lost so much of my fitness, muscle mass, etc. that I'm really upset about it... yet, I find it impossible to get my butt into the gym.
Part of it (I think) is that I'm used to seeing myself as "the fit one" and now I am sooooo not. I don't want to go to the gym as one of the flabby middle aged moms LOL... that just isn't "me" kwim? It's almost as if I want to be fit first, then go back, but that isn't how it works.
This is driving me insane because it is just NOT me. *I* am the one to encourage others and chide them about not going.
What is going on here and how do I get myself back on track?? HELP!
Lo.... trying to be the change I want to see in the world.