People are saying that exercise won't help you lose weight. I agree that you have to diet too, but exercising regularly (as you're doing) will increase your metabolism and you'll feel your body demanding more calories as your workouts get more advanced. Reward your hard work by eating HEALTHY and varied food until you are SATISFIED. Not binging nor starving.
As the others said, longer workouts burn more calories than short, intense workouts. If you can feel your heart beating, even if you're not going that fast, you're doing good. Keep pushing. But not too hard cause you'll get discouraged or injured.
I find that it's actually easier to work out every day rather than 3x a week (or whatever doctors are recommending) because a regular schedule becomes a routine part of my day and keeps me feeling healthy. This also allows me to vary the intensity of the workout without losing progress. If I'm not feeling it, I'll just go on a nice and easy ride, just to get out in the fresh air, move around, and then stretch. And if I skip a day or two it's no big deal. I congratulate myself if I've gone the same distance or more than the day before. And each time I feel I'm about to wear out, I try to push just a teensy bit harder. Then I coast down some fun hill and go home pleased.