Hate to break it to you, but that's some bad advice you've got there. If you let ammonia and nitrite build for three days, then it's more than possible you'll have dead fish by then. Ammonia and nitrite will probably be at highly toxic levels in three days.
They're also wrong about the bacteria - bacteria doesn't grow in the water, it grows in your filter. Water changes aren't removing any bacteria at all. The only way a low pH could be caused by water changes is if there's a big difference between tap and tank water. As it happens, your last test showed your pH was 7, which is bang on neutral. I can't imagine what kind of advisor would tell you to leave ill looking fish.
The system you're running right now IS working, but it's not going to happen overnight. Cycling, whether it's fish-in or fishless, takes months. If it's making you ill and you can't keep up with water changes, I'd advise rehoming the fish for now and starting again on a fishless cycle. It's boring and it takes a long time, but it's a lot less hassle.