Should I take him to the E.R.

My son will be 1 years old Friday his had had diarrhea all day today and he just vomited all over the place I just check his temp (anal) and it was 99.4 I’m a ftm and this is the first time this happened to him so I’m freaking out and I want to take him to the hospital. But my husband think I am overreacting and that he is fine and I should just wait till the morning and call his doctor. My husband think it’s just the heat making him sick but I seriously doubt it considering we been in the house most of the day today with the ac on. What should I do? Should I just wait till tomorrow and call his doctor or take him to the hospital now? Right now at this moment he seem like he is fine he is laying on the couch drinking cold water and watching tv with just a diaper on.