How do you heal after a breakup

I dated someone I loved. I gave him so much joy and he gave me so much happiness. Those memories I cherished. He chose to leave our relationship

It broke me I lost the man I wanted to grow old with the man I saw my future with it hurt so much it broke me I closed myself off

I stopped wearing beautiful clothes, I stopped waxing shaving I stopped getting pedicures manicures I stopped talking to people

I've been socially distanced for a long time

How do I let go of all of this

I don't let people get close to me.

How do I open up I'm a bit jumpy or I walk away I want to be more accepting of people but how?

I'm scared I guess I worry will people think I'm dumb that I'm a loser that I'm bad at things like all these things I started to blame myself for why he left me and it's frightening there's no guarantee someone will stay you can't force family friends lovers to stay only thing you can do is be genuine and hope they love you but I'm scared of that rejection so much that before people can reject me I walk alone and that loneliness is a killer.

How can I change?