The fleas could be part of the problem, however, we had a little beagel mix that would do that anytime her anal glands were full and she couldnt suppress them on her own. The next time you see the vet, have him or her show you how to squeeze them. They become painful for the dog when they cant empty them theirselves and it is relatively easy to do once you have seen it done.
I agree with melissajean though about getting rid of the fleas, that fumigation is the key, but if the area that the dog goes outside in isnt treated as well, then it really becomes a battle to win over the fleas. A very good thing to do is get a pet comb that the teeth are as close as possible and start brushing the dog at least once or twice a day along with flea treatment and destroy any fleas that come off the dog onto the comb. You can either put them in the toilet, add some toilet bowl cleaner, or get a bucket or container and put pure liquid bleach in it, but be very careful that none of the pets try and drink the bleach. Hope this works out for you.
if the fleas are all over you should try try really hard to get down to the vet and get some perscription strength flea&tic medicine, usually in a drop form. if the fleas have infested your carpet(and can lay dormant for months!!!) you need fumigation! tell your dad if he doesnt know already...im sure he doesnt want fleas in his carpet.