S-Self-sabotage

I am a master of self-sabotage.  I don't know why.  I used to not do this to myself.  I wonder if it's because I want to not trust myself to follow through on things because then something good might happen.
I don't feel entitled to things, but I do think that I deserve to be happy and successful.  But do I really think that?  I am not sure.  Sometimes I think that deep down inside I think I deserve to be unhappy and struggling with my weight and with money.
I am trying to ignore the negative voice in my head and do things that need to be done.  I've vacuumed and mopped the house for the first time in ages.  I'm going to change the sheets.  I am drinking water and I worked out.  I've written my 750 words and I'm doing this post.
I have more things to do but this is a start.  The working out helps.  It makes me feel like I am not letting myself down even though I have kind of slacked off for the past few weeks.  Of course, it's not like I really could work out while I had a bad cold or when I could barely walk thanks to my back going out!
I am trying to tell myself good things.  I want to believe in myself again.  I want to have life be easy again the way it used to be.  I don't mean that I don't think bad things will happen, because they always do, but I don't need myself to make life harder for me than it has to be!
I am going to work on my daily goals and not lose sight of my long term goals.  I know what things I need to do, and I'm not going to give up.  I think it's easier to give up but then I end up feeling like a failure and it's hard to win when you have that kind of mindset.
I wish I knew what the underlying reasons were for my lack of success.  I know it's due to my own actions, but I think I need to know why I keep sabotaging myself in order to stop doing it.