my cat seems to be sick

my cat seems to be sick

About a day or two ago my male cat seemed to start to act a bit strange, he drowls out the left side of his mouth and lays weakly almost all day long. He also seems to be very un-interested in almost everything. He goes over to the food and water bowl and smells it but doesn't seem to eat or drink any. Any suggestions to what he might have would be great or what I might be able to do for him. Thanks for the help- JIll