Sounds like you have a great attitude about your future, which is terrific. Confidence is a big part of the battle!
Take all of your volunteer activities - don't underestimate the value of them and the skills you used/developed - and turn them into bright spots on your resume. I know quite a few people who work as, or use the services of, coaches (life coaches, HR consultants, resume consultants, etc.) who help you present yourself (on paper and in person) in line with current expectations in the job market. They help you prep for the questions, refine your answers, etc. One friend who does resumes and is an HR consultant for employers too small to have their own staff (or who need extra people for an expansion or merger) cites her success rate (namely, getting your resume noticed so you at least get an interview). That would be something to look for in any person you consider hiring. The investment should pay off in helping you land a better job, sooner and at higher pay.
A lot of people use BNI and networking groups to help you make connections. A lot of people temp at first, either to get skills or to work in a temp-to-permanent setting. That's hard if you need child care because yo often get a temp call on short notice, but you can look into an ongoing temp assignment vs. a per diem sort of thing.
Hopefully you have a good lawyer and are getting appropriate child support to help cover day care costs - this is not entirely on you, you know.
I'd get those ducks in a row before you think about dating. You definitely need adult conversation though, so get together with friends on the weekends when your ex has the kids. Most of my newly-single friends have met the nicest men over time by doing things they enjoy doing, and meeting others who have the same interests. So rather than being "on the prowl", they've joined museums and churches/synagogues, done meet-up groups. gone to concerts or line dancing nights, joined a volunteer group or a hiking club, joined a gym, and so on. I know that sounds daunting if your time is so precious. My sister-in-law met her husband in Parents Without Partners. I do have one friend met her long-term boyfriend on Match.com (but she had to go through a lot of liars/losers first - her advice is, be honest!). But if you are busy doing things you like, you will more likely find interesting people who may or may not be your "match" but who have friends who are single. So don't be evaluating everyone as a potential mate, but as an interesting person who finds you interesting. My cousin met his wife when he was out with a big group of friends, and she showed up with friends of those friends, and well, the rest is history. The point is, they were all doing fun stuff and not specifically hunting for a mate or a date.
Good luck!