Question: Gulping for air a lot??

[Huskar]

Hello everyone!

I have a wild type axolotl and she's been gulping for air recently and I am curious that if its illness or just a normal behaviour. Shes currently sick but I don't know 100% sure if she's really sick, she has a swollen throat and her mouth is slightly open...

So she swims, plays around every day for at least 30 minuets straight, it's really fun to watch but she gulps for air like three times in less than 3 minuets, first two time when she gulped for air she sank to bottom and the third time when she gulped she was floating and she swims downwards like she's riding a roller coaster,, and she repeats that for 30 minuets straight.

I read some articles and Axies gulping air is normal but it also stated that gulping air multiple times like that could mean something's wrong??

My water test shows that there is 0 ammonia 0 nitrite 10 nitrate 7.8 ph
I do my water changes every week 25% sometimes twice a week depending on how much poop is on the sand.

Thank you for taking time reading this hope for an answer!