A list of things that you can do:
1) As soon as you get home, take your uniform out of the bag. If you can't / won't wash it between classes, then at least hang it so that it doesn't get wrinkled, and can also dry out quickly. Wet uniforms allow bacteria and other unpleasantries to grow and multiply, and the waste products they generate are foul-smelling indeed.
2) Take your hand pads, foot pads, cup and supporter, etc., out of the bag. Same reason as above.
3) Throw the bag in the washer. Add some color safe bleach, if possible. Let hang dry, or else it also becomes a breeding ground for the above mentioned microbes.
4) If you need to get rid of some really unpleasant smells that won't come out with a washing cycle, fill a container full of hot water. Add a small box of baking soda to the mix, which will first of all create an alkaline environment that will be unfavorable to many microbes, and second, absorb many odors / stenches that were trapped in your bag.
5) Get some Febreeze (if it's available in your area). Good odor killer, although this is only for a temporary thing.