I hope you give yourself credit for the twenty million things you're already doing in your life. It's easy to discount ourselves and just see what we haven't done yet...which only makes it seem bigger. I know this one...people have always told me I'm too hard on myself...and I attempt to take their words to heart.
My kids are now 9 and 12. I've been single for the last seven of those years now. It's hard, yes...it was a zillion times harder when they were even younger though... Now they know what "personal time" means and are much more caring of what Mom needs.
My biggest message to you, if I can help at all, is that it gets way better pretty quickly. Setting clear boundaries with your family as you go along is the hardest but most helpful piece of the puzzle. Knowing that you deserve as much for yourself as they do...and standing up for that...
You're learning difficult and useful lessons now though, that will give you your foundation for whatever you do next...like boot camp
Keep the faith,
Pam