Try measuring the various parts of your body. Waist, hips, thighs - whatever you want. You can weigh yourself as well, but as has been said, muscle weighs more than fat and your weight alters during the day anyway. The overall measurements of areas give a better idea as to if you have lost anything anyway. Also, you might not see much in the way of changes in yourself - you will change gradually so you won't see that you have lost weight as much as someone who hasn't seen you for a month and then sees you.
Again, as has been said look at what you are eating as well. I often find that if I'm not careful I go swimming/for a run/to the gym, and come back and have something to eat (chocolate etc) and probably undo half of what I have just done! Make sure that you don't go over what your calories etc should be a day, otherwise the exercise you are doing might maintain you at this weight, but not help you lose any.