So my son is 4 months old now and he doesn't seem interested in playing at all. There are times that he sits in his exersaucer and touches things but other than that he won't reach for any toys or grab many things. He's more content just laying on his back or rolling onto his tummy and making his sounds.

I know all babies develope differently but I'm slightly worried. Should I do anything in particular? I try to play with him all the time but he just gets bored and fussy.