Your post is very interesting. It sounds as if you know what to do to improve your life situation but somehow cannot get the fortitude to complete the task. I believe you are a lot stronger than you think.
I draw on my inner strength and a deep faith when I feel weak and frustrated. If I tell myself that I can do anything then it seems that I can. Maybe you coud find a simple sentence to repeat when you feel weak. I use the "eye on the prize" or repeat something like " I grow stronger each day that I do something good for myself".
I also put a small can on the counter in the kitchen. Each time I feel weak I write on paper something that "I CAN" do, fold it up, & put it in the can. When I feel weak again I pull out what I've written and enjoy thinking about what "I CAN" do. I know it's sounds silly but it works for me......something like that might help you feel stronger until you really become stronger on your own.