Buddhism teaches that most people suffer when the mind goes to the past or the future. It's very hard for modern brains to stay in the present because we have adapted for survival.
Another thing Buddhism will teach you is that there is no self because everything is impermanent. Because everything is changing and ultimately ending there really is no "old self"
Unfortunately, people forget that things are impermanent. For Better or Worse, things are meant to NOT last.
If we view life through this lens, then we realize every day is a new day and that every moment is unique unto itself. Likewise, we will stop clinging to things. We will stop attaching to things as if they were permanent. We will stop saying things like I used to do this or used to do that. It really is all nonsense. Nobody is the same person from moment to moment... every little thing changes us. But unfortunately many people think the opposite and procede to cling to things ( whether they are emotions, people, things, Etc) as if they were permanent, as if they were forever. But they're not. Nothing is meant to last. It's the most beautifully haunting concept you can learn and digest.
Buddhism can help people leave anxiety and depression.
If even any of this interests you, maybe I can put you in the right direction so you can simply learn more at your own leisure.
This does appeal to me, and I inadvertently kinda do this...now. I think maybe because I'm so detached from my "old self" that it doesn't exist anymore. It's more of an idea, or to put it in a better way, it's a warning. A warning of what not to be. I'm sure I cling to more than I'm aware of though