I think it's okay to feel guilty, shame, remorse, rage, or even hopeless about our past "mistakes". These are normal emotions, and we can't or rather shouldn't purposely avoid or even bury them. It's analogous to someone being dumped by a beloved partner and feeling like the whole world is crumbling. No matter how much we try to comfort such a person, he/or she will feel heartbroken.

In fact, feeling bad about our past is a great sign of personal development because it means we realize our mistakes! We can't improve ourselves if we don't even know what we did wrong in the first place. Hence, we should burn these memories hard into our minds and apologize to ourselves for making such mistakes. Then we should promise to ourselves (or even better, make concrete plans) to prevent repeating the same mistakes or to repair the damages (e.g., eat less or no meat, be more prudent in spending or donate more to EA causes, etc.)

Nobody is born a saint, so keep learning and growing into a better person :)