One thing at a time. Know the problem. Learn to listen. Learn to ask. Distinguish sense from nonsense. Accept change as inevitable. Say it simple. Be calme. How to work better, ten simple things that make a huge difference.
The person might not be who you thought they were; might have changed for the worse; but in the memories, they will always be the person you loved. it's ok to cherish those memories. You dont have to allow that person in your life now.
Surround yourself with the dreamers and the doers, the believers and thinkers, but most of all, surround yourself with those who see greatness within you, even when you don't see it yourself.Surround yourself with the people who love you.