redearslider.com

I've had my turtle for about 25 days, and everything was fine. Until recently, he wasn't moving much and he was always sleeping. The care sheet said that if my turtle is always sleeping, it probably means that the water is too cold.
So i put in warm water instead. But apparantly, the water was too warm. And my turtle went insane. He spun around in circles and flapped his arms and legs wildly. His mouth was open and his eyes were faraway. He looked like he was choking! I took him out and put him in cool water right away. But when i walk to him, he stops and ducks his head really quickly. And now he's not moving at all. what should i do?

First off, you need a decent themometer. If you have a hatchling it is even more important to have steady temps in your tank, basking and water. Hatchlings are more susceptible to catching pneumonia and respritory infections.

As for the current behavior, I would really recommend a visit to a herp vet. A good check up is always good. He can even do a better check than any of us on here can provide help.

Until you can get a visit in, make sure you know what your water temp is, should be 78F for a hatchling 72-75 for an adult. For now, because of the chances of sickness, you can even raise the temp to about 80-82.

I think he's feeling okay now. I saw him swimming around, but when i walked towards him, he stopped and ducked his head underwater. Anything I can do to make him not so scared? Or is time the best medicine?

Time.....

I've had mine 2 years, since they were hatchlings and they still fly into a panic when I enter the room. Some days they're not so bad but I don't expect it to really go away. All you can do is wait and see.

Okay, talking them putting them in cold water, then throwin them in warm water, then throwing them back in cold water is not a good thing to do. Make sure you have a heater and thermometer. Keep a steady temperature, you don't want to shock them with huge temperature changes.

I made a new set-up for him, and he keeps hiding underneath the bridge. He only comes out for food. Is that normal?

Considering what it sounds like he's been through, yes.