So I guess if you don't plan things, you end up just reacting to them.
And for the longest time, I punished myself because I didn't plan things enough - I thought that I found myself reacting to things so much because it wasn't something I'd accounted for, in my plans.
A lot of it was to do with my financial security - there was a period where I was making decent money, but failed to plan for the future, because I thought it would never end. Then, when it did, I was totally unprepared, and there was a much longer stretch where I couldn't prepare for the future, and so life was just... so much harder than it needed to be.
I think though, that while I was right to regret not planning and preparing while I was able, every moment of regret after recognising that - when it wasn't possible for me to do otherwise - was effort wasted.
Learn from your lessons, yes, but don't be a slave to your mistakes. The difference is whether you feel guilt - which you should - and whether you can do something about it.
Feeling guilty about not preparing for the future while you were able to is fine, but if you keep regretting not doing so while you can't do anything about it, it just becomes... draining. You end up punishing yourself, and it's just... exhausting. Tiring.
And to some extent, it's not possible to block this out completely. If you find yourself in a rough patch, and you could've prevented it, you'll think back to that time, and maybe resent past you for not doing so. The trick is to notice when this happens, accept that it's happened, and then try to do something better with your time.
And then to remember, next time you have the chance to prepare for the future, do it.