My 3 month old has a cold and diarrhea, what can I do?

My 3 month old has a cold since Monday morning and he threw up 3 times yesterday. He still takes his bottle and stays in his tummy. Now he doesn't throw up but he had about 6 poppy diapers since 6 am this morning. He is still a little bit congested and sneezes. I called his pediatrecian and they told me just to keep him warm, stop giving him milk and instead he told me to give him Pedialyte or isomil DA. Did any body has a similar incident? If so which one did actually help? Any info you can give me on this is really appreciated.