One of my 2 month olds has gotten very lethargic and sluggish. He was unable to walk and was only rolling over convulsively this morning. He was not eating or drinking. Now his head leans to one side and now he only lies there barely breathing. I've separated him from the others (who seem quite fine) and I'm at a loss to what caused it. I'm thinking heat stress or wasp/ant bite could be the cause, anyone with opinions,please help.