I'm curious, what is your calorie intake? are you exercising in addition to the calorie counting?
I used to be at just under 50 bmi about 4 years ago, and currently I'm around 23 bmi. It's possible, but you have to keep going. If you think your diet is too restrictive, then ease up a little. Cutting calories and incorporating some exercise will lead to weight loss, especially if you are following plan. But, if your diet is so restrictive that you think you're going to fail and possibly binge or cheat a lot, then may be you're not on the right diet. Good luck!
I'm currenly 28