What's wrong with my sick Kitten?

My 3m old male kitten has no been felling well for the past 24 hours.He usually is full of life and energy, but now he just wants to lay down.He can't seem to get comfy, and isn't even sleeping, just laying there.He doesn't want to eat as much either. He just seems very uncomfortable. No vomiting, diarrhea, or sneezing/coughing. His eyes had a little goop in them this morning.