So, you've had the tank 5 days, correct? Then, it isn't cycled.
What was it you said in your earlier post about boiling water?
If your breeder had gravel in the tank, then I don't trust him already. So, confirm everything he told you with people here - we will do our best to give you good advice.
First - buy a dechlorinator to dechlorinate your tap water. Seachem Prime is highly recommended by axolotl keepers. Avoid ones with aloe vera - some axolotls are sensitive to it.
Your pH is very low. That could be part of the cause if the pH is very different from what the axolotl was raised in. Do NOT raise the pH with products like pH Up. Instead, the generally accepted way to raise pH is to get some coral gravel in a sock or stocking (nylon, not cotton or anything that rots) and place it in the tank. This should slowly raise the pH.
Important rule-of-thumb - changes stress axolotls (and animals in general). The move from the breeders to your aquarium was a big change, especially if the water was very different. Being moved out of the tank so you could clean it is a change. Axolotls tend to not eat when stressed. Try not to change things quickly.
What are you feeding your axolotl?
What I recommend
1) Try hand-feeding your axolotl, or if it is scared of your hand, drop the food right in front of its nose. Don't leave any uneaten food in the tank.
2) Buy the dechlorinator and use according to directions
3) Get some coral gravel in a sock in your tank to help raise the pH slightly and add some hardness and calcium.
4) Keep checking the water parameters, but don't change anything quickly. When the ammonia and nitrite go up (they will go up - your tank isn't cycled), do water changes to bring it down again.
5) Read all of the "stickies" at the tops of the forums here. There is lots of good info.
6) Check all of the breeders instructions against the advice here.
7) Don't panic. :happy: