down 28 pounds, still fat

I had my first child 8 months ago, and I gained a total of 70 pounds during my pregnancy. 🍪🍬🤷🏻‍♀️
I have managed to go from 188 to 155. I'll do really good for about 2 weeks then I binge and gain weight. 
I'm really over it. I want to start Monday with no sugar, like soda, and no processed foods. 
My goal is 30-35 pounds in 4 months. 
I think writing this out will help. I've started planning yesterday what foods I can and can't consume, how much calories are needed a day, and how much I should walk a day. 
I've never been this big in my life. I'm embarrassed, and I literally can't wear any clothes and feel okay so I avoid people.  
Monday's my start date