How do I start all over

How do I do this? That's where I'm at right now. I'm disgusted with myself because I'm basically back to where I started and I'm not even trying. I'm actually doing the opposite - it's like I'm on a runaway train. Food in, don't feel the hurt, more food in, feed the pain, more food in, now your clothes don't fit, more food in, more food in, more food in. How do I get back into the mindset I was in when I was doing all the right stuff? How? Why don't I want to feel good, why don't I want to feel proud of myself, why don't I want my clothes to look decent again, why don't I want to feel winded when carrying my daughter around, why, why, why....
I don't know. Everyday I wake up I feel good about the day. That feeling is shot by the end of the day. How does something so important become not so important by the end of the day? How?
I can't tell you how disappointed I am in myself -
I suppose I'll wake up tomorrow and feel like it's a new day. God I hope it really is a new day because right now - I hate the person I am.