Grunting and straining.. Is he asleep

So my LO 5 week old has been grunting and straining and NOT crying ,, like he is trying to push out a poo, I suspect he has gas.. but when I go to check on him in the crib ,his eyes are closed.
Is he asleep??? He is making all this noise but then appears to be asleep,, well I'm basing that on the fact that his eyes remain closed the whole time. Do I need to do anything or should I try and sleep through it?