Carly: ignore the scale. Throw it out. Hide it from yourself. You have alot of weight to lose, which means the changes to your body composition as you do are going to be obvious, but the numbers on the scale might just drive you crazy. Water, inflammation, bathroom habits, gains in lean mass... you're going to interpret them all as gaining the fat back. So put it aside for a while.
Focus on being healthy. Eat plenty of veggies, meat, healthy fats, and a little fruit (in that order!!). Move more. Eliminate stress as much as possible and get plenty of good sleep. If you do those things, avoid "cheat" foods, and quit obsessing, you'll find that you feel better. And then you'll find that the weight will come off. You can do it!!
The headache is probably carb flu, but could also be a hunger signal (it is for me!). Make sure you are getting enough to eat. You may find that the portions you need look different when you eliminate grain-based foods.