You already messed up and you already tried to apologise. You can't make others forgive you, that's up to them.
All you can do now is learn from this experience, accept that you will never see her again (unless you want to go to jail) and move on.
If you don't want to lose more people in your life don't harass them and respect their boundaries. It's that simple.
If you can't stop thinking about her, go get some therapy and take care of your mental health.