If you suspect that you've been putting more into the compost the last week or two you simply weigh your garbage again for a few days. Just the same way as you did when you started the compost. Then you reduce the amount you put in to what you used to put in and then slowly increase the amount until you again can put all your waste into the compost. If your compost has been started just recently it's no doubt that the amount you put in there is to much for the worms, for now. Don't put anything in the compost until the smell goes away and then increase the amount of garbage slowly.
Bad odour can also come from a deficiency of oxygen.
If the compost seems very compact that's probably the case. You then mix a lot of leaves or sawdust into the compost and make sure that the compost is airy. You will probably get flies in your compost at least once. The eggs of the flies can be found on the fruitpeels and if the peels is not properly covered with bedding the eggs hatch and the flies can keep on laying new eggs. Cover all fruitpeels thoroughly and this should not be a problem.