Calli, the only way to lose weight it to eat less and exercise more.
When I plugged in your information to the calculator below, it tells me your body burns about 1400 calories per day, plus whatever you do for exercise.
So, if you want to lose 1lb per week, you can do it by eating 1400 calories and exercising off 500 calories per day. Or you can eat 900 caloies and do zero exercise.
You are asking what it would take to lose 20lbs in 6 weeks, which breaks down to roughly 3.3lbs per week. To do that you'd basically have to starve yourself and/or exercise non stop. Probably not going to happen (sorry).
Check out this site for information on your diet. Lots of good information there. http://recipes.howstuffworks.com/diet.htm
By the way, you're 5'10 and weight only 126....I would think that would fit anyone's definition of 'looking good'. Don't worry about it too much, guys are easy to please. Just talk to them.