Potty Training....Maybe?!?!?!?

I had just finished talking with my mom on Skype when Joshua came running into the kitchen with absolutely no diaper on. I had also just asked him if he needed a diaper change to which I got a very adamant "No" and a head shake.
I looked at him and asked if he needed to go potty on the sea turtle (his potty seat that attaches to the toilet). He took off running for his bathroom and tried to put the potty on the toilet. I put it all on and put him on the toilet in which hie did a really great pee-pee job. Then said he was finished. I helped him off and asked "Are you sure you're done?" and he said "Potty, Potty". So back on he went...at which time he peed a little bit more and then had a little poop too. I got so excited and clapped for him and told him great job. I asked, "Do you want a clean diaper or undies on?" He looked at me and said "Undies" and ran to his bedroom to the drawer that I have been keeping the undies in. He is at this moment walking around the house in a T-shirt and undies. I am paranoid that he is going to pee on our carpet or couches and keep asking if he needs to go potty and he keeps telling me no. I guess we'll see what he does today. I'll just stay on top of it.


UPDATE:
We made it a full hour before he peed in the kitchen. If anything at least it was in the kitchen and not carpet. He then asked to go on the sea turtle, where he went a little bit more. We'll keep trying. I'm sure he is getting the hang of it and he's starting to do it all by himself rather than us forcing him to potty train.