Just because you have left that toxic situation, doesn’t mean you’re automatically healed and shouldn’t care anymore. It’s okay if you still care. Give it time to work through.
Really, though. Sometimes it take a lot of time to work through it all. Sometimes there’s issues you didn’t even realize you had from it. Sometimes they spring up years later and you’re not sure why you’re even having difficulty with it. Just remember that it’s okay to not be okay. Accepting that you have to work through some things is a major part of beginning to work through them.