It seems you define regret as: if I went back in time I would do <Y> instead of <X> and of course this is a pointless exercise if you choose to define it this way.

Most people I think define regret more abstractly: back in time, <X> was a _mistake_, it shouldn't have happened, _I_ shouldn't have done it that way and consequences came from it either for myself or those I love.

It seems from your response that you're ok with admitting your mistakes which - by the above definition - sounds like you feel regret.