So first I am going to have to tell you how I ended up with my very first Betta.
On Thursday(Dec 9th) A bunch of friends and I had a christmas party. We played White Elephant. In White Elephant there are four bowls with a pair of dice in each. The bowls pass around and you roll the dice, and every time you get doubles you get to trade gifts with someone. Right away I decided I wanted to end up with the weird white box that had 'fragile' and 'this way up' written on it, which I did. At the end I opened it to discover a red betta in a clear glass christmas ornament.
Well my friend who had brought the gift told me everything he thought I would need to know about bettas, much of which I am now learning is wrong. Dispite the fact he told me my betta would be perfectly happy in the ornament I went and got it one of those little tanks from wallmart, and did the transfer. The day after he was still acting lethargic and he spent most of his time at the bottom, and whenever I drop food in he doesn't even show a flicker of interest. So I got on google and started to research, and discovered how wrong my friend had been. I have no heater but I am keeping my dorm room nice and toasty until I can. He is acting a bit better. He hasn't been on the bottom at all today, not doing much swimming though, and still has shown no interest when I drop food in. I am a sophomore in college, and there is a strict no pets policy in our dorms, so I am keeping it hidden, which I can do since the tank is small, not sure if I could if it was a two gallon tank like you all suggest. I am not even sure how big this one is, that info wasn't on the box.
So I guess my questions are
Why isn't he showing interest in his food?
Why is he being so lethargic? Is he still recovering from what must have been a terrible ordeal?
What kind of heater? The smallest I could find was for a two gallon tank. I don't want to cook him.
And Any other useful tips?
THanks
Oh and his name is Firestorm, pictures bellow.

What I got him in

His current home.