Dear LaLa77,

I am so sorry to hear about the breadth and depth of your journey over these past 10 years. I am the parent of an only child as well and just reading the beginning of your post stopped my heart in its tracks.
Exercising is supposed to be amazing for all sorts of mood issues, never mind the health benefits. And trying to get out there socially must have been a big step for you, too. Yay you!
Is your car still broken down? Did you meet anyone in exercise class or at the meetups that you could ride with? Or are there other modes of transportation? (I know that that is a long shot except for a few locations in the states, but you never know.)
Do you think talking to your sister about rebuilding your relationship would help? Or asking your ex why he is uncomfortable with you maintaining a relationship with his child?

I know all of these things place the onus on you (and, hey, I am horrible about exercise, and it took me years to get on a forum) but even if you take one tiny step, you might feel better.

thinking of you--
bookmadness