For how long he is having this condition?
the last 4 hours
If he is doing vomitings for last few hours then he is dehydrated.
Disorientation and sleepiness is sign of dehydration.
Vomiting can occur due to any infection like throat or uri.nary tract
it all started when he woke up from a nap
Food poising also lead to this.
Look like he is having some infection.
could he have swallowed something? or from something he ate?
You need to give him oral rehdrating solution after every vomit.
Best is taking him to doctor.
There is less possibility of swallowing some thing.
what is oral rehydrating solution? like pedialyte?
Food poisoning can be one reason.
he seems to be getting better with the walking and standing as more and more time goes on.
Keep an eye on his temperature.
but he still continues to try and sleep for a few minutes intervals
If he improves and is playful then all is fine.
Excessive sleepiness when he looks disoriented is not good.
what would cause these symptoms
However,if he is playful and sleepy in intervals then its fine.
Vomiting is causing loss of body salts hence its causing all.
vomiting itself can be due to infection most commonly in this age group.
Try to check his throat.
Any more questions?