fine line to staying home

Two days ago Theo was complaining about a tummy ache when he woke up from his nap.  He did look out of it and was not his normal self.  This was also followed by a morning full of fruit, smoothie shake and the night before a sold hour of chips and salsa (when we were at a party in the park).  So a tummy ache was par for the course- I thought.
Two nights ago he was up every two hours- crying, wanting juice and so on.  In the morning when he got up he was congested with a runny nose- he told me his teeth hurt.  hmmm.... this is usually a common shared gesture he likes to act out with baby to get a teething toy- except this time he was pointing to the back of his mouth with his finger.  He was still all play and full of energy, so I decided I would do the frowned upon and take him to his pre-pre-preschool- I would just be quick to wipe any signs of runny nose so we wouldn't get busted.  He played at school- did two paintings, studied the jars of bugs Ms. Miriam brought in for the kids, sang and of course was first on the bench for snacks under the eucalyptus tree.
In the afternoon he wanted to go for a bike ride.  It was too hot for the park, but a good bike ride to the new house or the tree cutters down the street would be the perfect outing I thought.  Two blocks into the ride- he jumped off his bike, wanted his helmet off and cried telling me his tummy hurt, he's tired and wants to go to bed.  One other challenging request- he demanded that I carry him home.  This of course was tough- I had the baby and the bike.  So I left the bike at our neighbors  (2blocks down the street) and carried the two of them home.  Honestly not much pitty was being spared for him at the time because I could feel my back using every muscle- probably for the last.  At home I put him to bed and listened to 40 minutes of old macdonald and ABC's- then he was ready to get up.
I couldn't figure out- what was the deal... are you sick, tired or just mimicking something that you heard over the past week (i.e babysitter was sick with a tummy ache one day).  At first  you think it's lucky you're at a stage now where your child can tell you- communicate needs, but then you realize most of the things they communicate have been recycled from other conversations they've heard.
This morning I'm waiting to see what the nose situation is when he wakes up.  I'm not worried- because we can take it easy if it seems he is still not 100%.  Also, this week Pheobe and Theo have their Doctor appointment on Friday (both get check and shots)- could be a traumatic  day for us all!