Congratulations on your accomplishment! You SHOULDN'T feel guilty since you worked for it, nobody "gave" it to you. I think the problem is that the decision was made rather quickly, and you didn't really have plans other than leaving. You'd probably fell less guilt if you had been running towards something in "retirement" vs. running away from "hell". Chin up, and start living the life you want and doing what makes you happy. No ones says you can't work any more, but FI gives you freedom to choose what, how and how often you do it.
I personally love my work but i do see myself being a semi-retired person at your age as well. My original goal was 60, but i think I can bring that down. I started investing much later, and as a single parent it is a bit harder, but it can be done once you put your priorities in place. I give big props to MMM and this community for bringing clarity to needs vs. wants, and promoting living a great life without consumption.
Go forth and enjoy!