He probably threw up his bottle because all the gook from his cold gagged him.

It is such a hard call on when to take them in. My DD gets ear infections with most colds so I usually end up taking her. Of the last 3 times we have gone in she had an ear infection with one of them. I always feel a little silly about it, but it is so hard to tell when their ears are hurting. My best advice is to just go with your gut and give a call or go in if you think you might need to. It is no big deal to go in and have everything check out OK.