Milo throwing up, arghhhhh

Hi there, I just wanted to see if anyone else has a similar problem.
Milo Buttercups sphynx, has not been himself latley, he seems to be sleeping more. I had noticed a few times in the past week and half that one of the cats had been throwing up... Not hairballs or bile, but there actuall food.
I have been assumng it was milo but not sure as we do have 5 cats.
Talked to a local vet tech who runs a pet food store and she suggested changing foods to nutram sensitive stomach for cats. Which i did, so all 5 are on it(friggin expensive) arghhhh
Anyhow, yesterday, i actually caught milo throwing up, so called the vet right away and got him seen. He also pooped so i took that with me.
The stool sample came back negative... They have done some blood work and are awaiting the results.
The vet thinks it may be a inflamed digestive problem (probably saying this wrong)..... Or that he may have eaten something that he shoudnt have ie: an object, that is floating around in his tummy.
We are hoping the blood work comes back all normal. Next step I guess would be xrays....
Has anyone had this problem? The vet says cats can just develop a digestive problem like this



Ps. i posted this in the wrong area before, think....

Sounds like you are doing the right thing but taking Milo to the vet and having the work up done. Does Milo eat too fast?? We had a cat that did that, so we divided the meal into 2 parts, with a 45 minute wait between rounds. That help stop the vomiting. You also could ask the vet if giving Milo a quarter of a 10mg(2.5mg)Famotidine(Pepcid the trade name is mosre costly). about 20 minutes before he eats, that may help!!! Good luck!