Was anyone else worried about becoming a civilian after 20 years? I don't know where to start to keep supporting my family. Any good advice?

Stop worrying
Have a exit plan.
Don't walk out blind

1) Inventory your assets - Time, Money, Education, Skills & Talents, Contacts & Allies, Passions & Interests. (Things your good at or enjoy that seem like they do not pay. If you need cash for a hobby, someone is making money on the peripheries of what you do for fun), Spouse employment potential, Real Estate etc.
2) Inventory your liabilities - Debt, health issues, Future Obligations (care of parents, children's tuition, etc)
3) Decide what MISTER Pellerin's perfect world looks like 10, 5, and 1 years from EAS, in that order. Employed, Self-Employed, conventional work environment, unconventional work environment. What metrics will you use to measure success or failure?
4) Contact people who are where you want to be in your perfect world snapshots. Ask them their advice to get on that road. It doesn't matter if you know them or not. Be up front tell them what you want, what your circumstances are and that the only thing you can offer them is a cup of coffee and a doughnut. Most will help you, willingly.
5) Take their advice where you can. Ignore them when they say you can't. Cut the distractions and dead weight. Formulate a plan that fits you and your circumstances. Beware opportunities that are dead end or distractions. Never stop scanning for opportunities (position, education, contacts) that support the plan. When you've got your plan go back to the coffee and doughnut contacts for a reality check.
6) Regularly assess your progress. Commit the reserves to reinforce success. Do not spend assets to repair failure, move on.

If you hate your job, you will never feel well-compensated. If you love your job, you'll find a way to get by.

Much depends on you financial status. Don't rush into anything unless you have difficulty making it. I actually went to school and drew unemployment (the only time ever) while looking. After about a year, I got nervous about my employability and took a civil service job. Biggest mistake ever, it was like being in the military, without the good parts. Take your time and find a job with growth potential. Good luck! I never looked back.