I love this guy and was a yandere towards him, I threatened our friends, was clingy to him, and now he doesn't like me at all. How can I still earn his love?
This is not love. Infatuation or obsession, more likely. You acknowledge that your behaviour hurt him, yet you seek to make amends, not for his sake but to regain approval or affection. It's a selfish desire, and that's okay - not uncommon.
But you shouldn't try to fix things in this stage. You need to learn to respect boundaries first.
Example from Marcia a real life experience.
Learn from what happened she says. I ask myself "‘Has this experience revealed any areas in which I need to grow? What, if anything, would I do differently in my next relationship?’ “After time passed, I could better analyze what happened,” However, I had to wait until I could look at things rationally rather than just emotionally.” It took a year for me to get over the breakup. It took even longer for me to turn the experience into something constructive. What I went through taught me a lot about myself, the opposite sex, and relationships. I feel much less pain now about the breakup.
God created us with the ability to heal. It takes time to fall in love with a person, and it takes time to recover when your relationship with that person ends. But it can be done. The heart does heal
For free downloads, publications, videos jw.org search for the book"Questions Young People ask, answers that work Volumes 1 and .2.