potty training problems

HELP!!!!

My son turned 3 in October.  I had tried potty training off and on since he was about 18 months old.  Sometimes he would do really well, and then he would just have no interest and I would stop pushing for a while.  Finally, the week before he turned 3, something "clicked" in his little head and he was ready to use the potty like a big boy.  Boy were we all excited.  We even got him a sticker chart and told him he got one sticker for #1 and 2 for #2 ONLY if he used the potty.  No stickers for accidents, but also no punishment (accidents happen).  He filled the chart, with a lot fewer accidents than I expected, and got a prize.  Things were going great!

But then.....I don't really know what happened.  It seems like we're back where we started some days.  He's been peeing his pants quite often the past couple weeks.  A lot of times he'll realize he has to go, but instead of just going to the bathroom, he starts running in circles, panting and yelling "I have to pee" until we make him go into the bathroom.  Then there are the times when he's playing and I guess he just doesn't want to stop so he'll pee his pants.  But the ones that are really starting to concern me are the times when it doesn't seem like he even knows he did it.  I'll notice his pants are wet and ask him if he peed and he'll say no.  I have to actually show him the wet pants before he "gets it".  I also started asking him if he needs to go a lot more often.  Most of the time he'll tell me no and then 30 seconds later Heather wets himself or starts screaming that he has to pee.

So, what do I do?  Is this normal?  Is there possibly something wrong?  Should I make an appoint with the pediatrician?  Should I just wait it out?  I am just so stumped as to how to handle this.  At times I think I should take him in, but then I think "no, he's just bull headed".  (and he is.  This kid does nothing unless its on his terms)  So please, any advice is welcomed and appreciated.  Thanks!