It sounds like you are doing everything you can. Taking him to the DR and trying to keep him comfortable is about all you can do right now. Kids are so strong.....just keep a close eye on him and if he needs to go to the ER just be the momma you sound like you are to him. Reassure him and love him.
It sucks when your baby gets sick, you feel so helpless. Just don't let him see you feeling bad...that only gives them more reason to fuss. Be positive around him and tell him he will get better soon.
Keep us posted on how he is doing