I feel like I always have things I regret.
Does this have to do with a personality trait of yours?
I always regret something because I feel like I always let myself to get disappointed.
It's okay to feel regret but you shouldn't feel regret all the time. You should learn from things and move on.
I'm trying, but I feel like I'll never get back what I lost.
It's normal to have feelings like that, but all you can do is learn your lesson from your past mistakes and move forward. Dwelling on your regrets will only leave you stuck in the past, unable to make progress in your life.