Illness/Sickness: Newb owner: Axolotl lost gill frills overnight, what's going on?

My axolotl Trent lost most of his pink gill frills in a period of about 24 hours. Yesterday afternoon they were curling inward (the frills, not the actual stalks they protrude from) and this morning they're almost completely gone. He's acting kind of strange and isn't responding to me how he usually does. Last night I played with him in the water while I fed him and he was biting me as usual but this morning I put my hand in and he flipped out, darting around the tank. He's refusing to get in my hand which he normally loves to do when eating.

Here are his tank conditions as of this morning:
pH >7.6
High pH 8.1
Ammonia 0.25ppm
Nitrite 0.00 ppm
Nitrate somewhere between 5-10 ppm

I don't have a thermometer so I couldn't get an exact reading but it feels about 68-70 F to touch.
His tank is 10 gallons with an Ovation 210 filter. I have the tank filled to about 7.5 gal.

His pH levels seem high to me, could that be what's causing this strange behavior?

I'm a new owner and freak out at pretty much any sign of discomfort or illness for him. I've had Trent since September and he's been happy and healthy except for this one instance.

I've attached two pictures of him as of this morning.

Any help or advice I can get is greatly appreciated.

The ph is a tad high and may be causing the ammonia to have a stronger impact on your axolotl. The presence of ammonia suggests your tank may not be cycled. It is very difficult to determine an accurate temperature without a thermometer so it would be best to get one to rule out temperature as a factor.

Thank you for replying! I've been worried sick all day. I retested the water and found that I had incorrectly measured at least the nitrates. The new measurements are

Nitrate: 40-80 ppm
Nitrite: 0.00 ppm
Ammonia: 0.25 ppm
High pH: 8.1

I bought a thermometer at the pet store today when I drove over there to get help from the guy who sold my axolotl to me but once I got home I realized it was broken. :uhoh:

Tonight Trent is looking much better. Some of his colour has returned and he's swimming around and interacting with me even when I'm just looking at him from outside the tank. His gill filaments are still much shorter than before and I do think they're somewhat damaged, but he continues to show no sign of fungus or illness on the rest of his body.

I considered that he could actually be a she, and perhaps she was laying an egg but the guy at the pet store said that was pretty unlikely at Trent's age.

Any tips on how to keep this from happening again? (Other than buying a new thermometer, which I will do ASAP )