I dont know what you are referring to, but I think you should feel free to grieve the loss of some hope and optimism, and give yourself space to do it in anyway you need. That sense of disconnect from yourself is a common thread in grief, and I think you could explore it further to see how your current self is just as valid and worthy of love as your former self.

The transformations we all undergo throughout our lives shouldn't be seen as a straight trajectory or progression, but of a intermingling, meandering path through good and bad and everything in between.

I hope that wasn't too vague. Grief is on my mind a lot at the moment.