Some great advice here - it's all been said really, but with a 30-yr professional in my family, I feel bound to re-emphasize something.
"I don't have any business or marketing education" <-- there's your problem, as they say.
Most of *any* business is business and marketing.
Check out this chart -- there are similar ones around:http://blog.stanleyleary.com/2012/01/where-my-time-goes-as-full-time-pro.html
But there is hope - you now also understand why you are probably having trouble getting something in your existing profession too!
Clearly you have the skills and experience as a great graphics designer. All that's likely missing is the business and marketing skills to sell yourself to potential employers - or even to make it yourself in your own business in the same field.
Go for it. Get that education. Find free or low-cost classes - fantastic MOOCs like Coursera/Udacity/EdX, etc. Even just YouTube. Also your public library. Use that time you now have as an investment - in you.
Good luck! But heed the advice in this very fair thread carefully and "seize the day"!