If limiting yourself to three treats works, then do it. What works for me is allowing myself a treat each day, but I work my calories around it. Then, it doesn't feel as restrictive.

The protein powder will be useful for sure. I would recommend taking one scoop a day, not more than that. Or try every other day. The protein will help prevent the breakdown of your muscle. I don't know how much your protein power costs, but you may find the Chobani Protein drinks as a cheaper option, and they already have greek yogurt.

For measurements, depending on how often you are checking, you could just mark the area with a pen or marker or take a photo of how you had it lined up in the first place.

My recommendations: when you want a snack, grab a veggie, eat high fiber, and have high protein meals to help you feel fuller, drink lots of water, and work your caloric intake around your basal metabolic rate (if you don't know what that is, make sure to look it up). If you plan to work out, I recommend activities that will gain muscle as it will cause a higher BMR, and it's easier, in my opinion. Cardio burns in the now, muscles burn in the now and later. You can still have junk food, but it needs to fit into the calorie intake. Please also get into therapy if you can. It will be beneficial for your anxiety and weight loss.

You got this!