This sounds just like my two nephews, 3 and 5, who found out on Sunday that they have pink eye. It's pretty contagious but you might want to call a doctor for your little guy right away and limit the number of toys he can play with to ones that you can wash easily. You both need to wash your hands easily and everyone in the house needs to be sure to keep their hands away from their faces. I guess an obvious question is are their eyes a little pinker than usual?
This is all so fresh from the several calls I fielded from my sister in law yesterday so I went straight to pink eye but having not seen them, I'm not sure what it looks like. I see you are new here--welcome! There is a nurse line you can call for kids in San Antonio to check out the symptoms. It's 210.22.NURSE. Since they are not seeing your child, they will always say to take him to see a pediatrician if you ask if you should. I think it's a liability thing. If it is pink eye, he needs antibiotics.
We have used Texas Med Clinic at 410 and Broadway as well as one on Blanco near West but you can check out all their locations at http://www.texasmedclinic.com/locations/index.php
I appreciate my kids' pediatrician. We go to ABCD Pediatrics in the Stone Oak area. You can check them out at http://www.abcdpediatrics.com. We see Dr. Gonzalez and the kids love her. When they are ill, they are always squeezed in. There are several doctors in this office so if your ped is on vacation, someone can always see your kid.