All I can say is that they were much higher before the water change, which is pretty scary when you think about it. But keep in mind that when you're doing a water change you're only diluting what's in there already. Another water change in your future tomorrow, I'd guess, and again until the ammonia and nitrites are down to 0. Anything above zero is doing harm to your fish.
My husband wasn't believing this stuff either, until he lost two beautiful German Blue Rams. It's making more sense to him now. It's taken me many, many months to get a good grasp of what I should be doing. I thought keeping fish was easy. Hah!