people who own and lead businesses risked their lives to get them where they are, made tons of sacrifices, they re not risking it all for someone who "changed his mind"; when you re done with an employer, you re done, period, no coming back.
You cant joke with business.
Just find something you ll enjoy and forget about it, werent there reasons why you wanted to leave in the first place anyway? You just sound like an immature kid to them, learn your lesson and find something else, that's how it works. They ll just put you down even more if you beg them and still they wont give you what you want.