Hi everyone,
First off, I'd like to thank you all for your sweet messages. It really helps in times like this to have people like you behind me.
I brought Oliver to the vet and they took him right away. His temperature, weight, teeth, and gums all looked normal. They took him in the back to x-ray his belly and to run a bunch of tests...liver, blood sugar, etc. Everything came out normal, and the vet basically said that it could be one of two things. Either its the start of epilepsy, which she thought was a long shot because it usually starts when they're a few weeks old (I don't know this for sure, just what she told me) or it was just a freak occurrence that was possibly caused by overexcitement. She gave me some special food to settle his stomach and wants me to bring him back if he throws up again or has a similar episode.
Sooo...he's back home with me, a little more whiny and needy than usual but I guess that's to be expected. Lexi is being a concerned sister and has been smooching and licking Oliver since I brought him home
THANK YOU again to everyone for your advice and good wishes!!!