losing weight is so hard

Why does it have to be so difficult..I eat well..yes occasionally i do eat potato chips or candy, but its not an every day thing, i don't go wild. I don't exercise much, but who does?? I do walk to work a lot ..yes true its only 8 minutes....but i do it..i even go super speedy and do it in 5 minutes sometimes..i speed walk around town for 20-30 minutes a couple of times per week..when i say speed walk, i don't mean that funny walk they do at the olympics, just fast walking. I also jump on the Wii fit and do dvds sporadically..i feel that it should be enough..and it does seem to be enough to maintain my weight..but it never seems to shift, not even when i up the exercise and deprive myself of things i want to eat such as cheese and bread.
A friend at work has successfully lost weight doing the Du.kan diet..thats one where you eat only protein for a week, then alternate only protein with protein + certain vegetables..it sounds easy..but im sure its not..i want to try it..but i don't feel like i have the will power to do it right now..and im not sure i should be trying to lose weight in such a severe way when trying to become pregnant. Im not enormously overweight, though the Wii fit tells me i am just under the obese category with a BMI of 29. I can still buy clothes at every day stores in the average range. But i would like to trim down a bit. I guess i am just going to have to become more diciplined with myself and make myself move more..grab out the weights, stick on the dvd's and eat no junk food at all...does cheese qualify as junk food??LOL