Carter's sleeping issues

Not sure what is going on with Carter lately. For the past three nights; about an hour after Carter has been sleeping, he wakes up crying.
I go into his room try and comfort him by rubbing his back and telling him it is okay. He acts as if he can't get comfortable, sitting up crying then laying back down rolling from one side to the other, then sitting back up again. During the time of him crying his eyes will just barely open and then close again, almost as if he isn't really awake. It takes me about ten minutes to get him settled back down again. Then about two hours later it happens all over again. I don't understand what could be causing this. He shouldn't be teething again already, so could it be night terrors? Could it be growing pains? I am not sure. I want to always make him feel comfortable and safe.

While writing this I looked up on Google, Night Terrors with toddlers and came across this post on the Baby Center site: Why is my toddler suddenly waking up hysterical at night? I saw that below the post there are a lot of other parents comments about the similar thing happening with their kids, and a lot of them are around the same age as Carter, 25 months. I can see this isn't that uncommon.

I remember when Carter was a baby and he had nights of not sleeping that well, it happened a week or so before he started doing something new like; crawling and walking. Maybe this is happening because he is going to be actually going on the potty when he says he has to pee. 
For at least the past month Carter has been randomly through out the day asking to go pee, we take off his diaper, he sits on the potty for a minute and then stands up saying "done!". We look in the potty and, nope, no pee! We continue to take him even though he doesn't go because we don't want to discourage him. We know eventually he will start going pee on the potty, I just can't wait until he does go. Then I can say good job that was peeing on the potty.  Sorry, I am sitting here writing this and thinking about what could be causing him to wake up crying and writing down my thoughts in the process. 

I will write an update to how long this last and if it seems like he is doing anything new to maybe explain why he was waking up freaking out.