disappointed

I have been battling porn, 4 years now. I started when I was 18. Early this year I was introduced to this site and after reading most of material here I was inspired to ask God for help and just to make effort to change. Now I know that its possible to lead a porn free life and be happy and fulfilled. I had a run of 2 full months without porn and Im in pieces for I have just broken it. I feel sooo guilty and dirty and just useless. I know its gon take a while but I just wanna keep at it, be strong and enjoy life without this filthy life-absorbing sin. Now I know its possible, I just need more courage