Should I take a chance?

I feel like i am so new to dating or having a relationship again, its been 4 years since the last time i was in a relationship. Usually people are happy and excited they in one or doing something great, I did feel that way at first but I don't anymore, I feel depressed and like I am just going to be unhappy...sounds kinda selfsih I guess, but hell I feel down. Nothing really bad happened but I am depressed, rebellious and feel like breaking everything off, everytime someone gets close to me emotionaly I tend to find sooo many reasons of getting as far away from that person as possible, could this be because of bad relationships in the past? everything begins to bother me, I cannot for the life of me see the posative anymore in a relationship and am scared shitless of getting hurt. In honest truth I want to try and be in a relationship and see it as being happy... but everything leads me to running away and sweeping it under the carpet like nothing happened...opinion,suggestion...somethin…