50 lb lost...??

Isn't 220 - 180 40lb? Have less weight to lose than you thought :-). When I started I had 31lb to lose and lost 10lb in 9 weeks. There's 22 weeks until August, so if you lose 2 lb per week you'll reach your goal. Although my average is 1lb per week. Even if you don't reach your goal by August you will reach it at a later date. Don't set targets that aren't possible to reach otherwise you may get disheartened. Also if you're exercising perhaps set your goal on inches/clothes size rather than weight. Good luck with your weight loss journey :-).