Why do I have such low self esteem?

Ok I must admit I have put on a few since I gradutated high school in 2004, but it doesn’t seem to just be that, I just totally can’t seem to except my body and it is really effecting other areas in my life like my marriage, my social life, and my sex life. I know I could loose the weight, but this depressed state the weight gain has caused makes me not care anymore. Whats wrong with me! It seems that since my personal image is so important to me, that it would be the normal thing to take the initiative and just diet and work out and loose this weight that is causing all the problems, but its almost as if I dont appreciate myself enough anymore to do anything about it. Ok that’s my ordeal in a nutshell, hopefully there are some psychologist online tonight haha. HELP!