Hey Cassie, your journal sounds very familiar. I've always had trouble with my weight, and I was the same age/weight as you are when I decided to get serious about losing weight. It's really tough, especially in the beginning. What worked for me was to take baby steps.
It took a lifetime to develop the eating habits you have now. You can't just wake up one day and change the way you think about food. But if you change a few of your behaviors – cutting down on junk food and soda, trying to make at least one meal a day “healthy”, and just stick with that for a while – you'll find yourself seeing results. Then you'll be able to build off of the positive feelings that you get and take the next step, and the one after that, and so on. And over time, your behaviors will start to change your attitude, and you'll find that each step comes more naturally. It'll never be easy. We live in a society that bombards us with images and messages to eat crap and body images we can't possibly live up to. It's a double set-up. So trying to fight against that all at once is nearly impossible, and can make you feel overwhelmed, like it's impossible. But it isn't! You can do this, but you have to stop beating yourself up. Yes, you ARE responsible for what you eat. And taking responsibility is important. But that's not the same as taking on shame and guilt.
Maybe you should try setting some small, very concrete goals for yourself. Example: Only drink one soda a day. Try that for a week, and then up the ante. I think your August weight loss goal is very reasonable, but August is a long ways off! It helps to have smaller, more immediate goals to work towards as you reach for your ultimate goal.
I've also learned to keep a lot of healthy, low-cal snack food around. I'm a “bored” eater, too. And I totally pig out when I get in the mood. I can't stop myself quantity-wise, so I try to balance it out by eating something really low cal, like carrots or rice cakes or whatever. I still eat the good stuff, but I'm able to eat smaller amounts because I stay full from eating lots of the healthy stuff. It might take some time to figure out what works for you, but the important thing is that you try things, and learn (not punish yourself) when you struggle.
So don't lose heart – You can absolutely do this!