You just have to learn to accept the things that happened can't be 'un-happened'.
You do your best to be the best person you can be and go from there. You gradually move past the past and start looking towards your future.
It may seem impossible when you're feeling down Beth, but it can be done. Once the changes you've made really take front and center in your life, you'll have no reason to look back with remorse or regret. Let it go, and move on.
You've come a long way from where you were... don't let this take you back there Beth.