Is it teething?

Hi mummies, my baby is almost 6 months. He used to sleep properly previously but last few days he has been waking up a few times at night fussying or crying but with his eyes shut ( most of the time) . Even during daytime he is only taking 2 naps. Rest is all 5 to 10 mins. Could this be because of teething? If its just a phase, roughly how long will it last? I do not know what is bothering him.