Bi-Polar?

Please tell me I am not alone.  I truly believe my pre-schoolers are bi-polar.  I got home from work.  They had just laid down.  I went to tuck them in.  They were the sweetest, most lovable kids.  I could tell they were keyed up, but still oh so sweet.  Came downstairs, logged onto FB, expected to goof off while the Mad Scientist finished dinner.  Instead, I sat listening to the monitor.  My kids were so freaking cute!  They were talking to each other, having fun.  The giggling was infectious and I was smiling from ear to ear.

The Mad Scientist and I decided to wait until 8:30 (an hour after bedtime) to let them talk and giggle with each other.  Around then, I went up to find out what they are doing.  They were pretending it was the Dancing Queen's birthday.  They were signing happy birthday, Ma and Papa were there, as were the Editor, Car Guy, Little Car Guy, and the Chef.  They were having the time of their lives.  Yet, I managed to convince them that we would play birthday party tomorrow, we'd make party hats and pretend cake.  We'd sing and we'd pretend the entire family was there.  After we pretended it was the Dancing Queen's birthday, we'd celebrate TRex's birthday.  I even convinced them that they could dream about birthday parties tonight to prepare.

Well, I thought I had them convinced.  They were quiet for a couple of minutes.  Then, over the monitor comes the giggles.  They were back.  They were still so stinkin cute.  We were loving it.  But, we knew the kids were on borrowed time.  Both are sick and haven't been to school for three days.  They needed to go to bed.  The Mad Scientist went back up and asked them to go to bed.  They giggled a little more and when it went from giggling to screaming, the line had been crossed.  The Mad Scientist went back up.

Here is where my sweet and cuddling children turned into pure eeevile.  TRex was adamant that he was not going to sleep.  He threw his puppy dog out the room, the one he has slept with every night since he was a wee baby.  When forcefully told he had to go to sleep, he screamed, he yelled, slammed doors.  The Dancing Queen was fine, then decided she was going to misbehave as well.  We had to take her pacifier (she only gets it in bed and she wasn't sleeping).  Then all hell broke loose.  Both were running around the room screaming and upset.  It was beyond obnoxious.  They were true devils.

Eventually, we got them back in bed, sleeping and quiet.  But, you tell me.  Am I alone?  Or are other people's pre-schoolers bi-polar?