Struggling to walk away from the past

I try to change myself to somebody else by buying all those things that I didn't even look at them before,engaging my myself in all kinds of activities and even learning how to scold others for bullying me. The only reason for that is to help me to step out from the shadow of the past. The past just tortures me so much that I don't want to have anything associate with it anymore. But, the past is still part of me.I realized that nobody can walk away from the past no matter how hard she tries. There are countless times when I was bullied for trying to be nice to people. I thought they will understand that every single relationship is a gift from God so we need to appreciate people around us,especially those who love us. But then,people start to take advantage of me. It seems like I really need to protect myself from getting hurt again. But whenever that happen,I cry, asking myself why should I treat them so nice and end up hurting myself.I am so vulnerable and so weak. My heart has been broken so many times that I become a person who lives in the dark because I am too afraid that brightness will reveals all the pains that lies deep down in my heart. Maybe I should keep my sadness to myself even though it starts to be a burden for me.