Baby boy has changed personality all of a sudden and something is a little off :/

[sarahhoping]

my 5 month old baby boy has suddenly changed his personality and his dad feels it more than I do
my baby still is active if one goes nearby and he follows objects and try to grasp them and put in his mouth, but the intensity and joy behind this actions are lesser now since yesterday morning :/
earlier he used to pull his dad's beard and then his hair and tried to devour his dad. he and his dad enjoyed this a lot, but right now he mostly ignores them and even if grasps them, leaves them quickly .
he seems a bit off and sad and we don't know why :(
although he still laughs and smiles at me
could it be because of teething ? he's not erupted teeth yet

How long has he been like this?

If it's just one day, then I would say possibly he is having an off day and feeling poorly, it could well be teething starting.

See how he is tomorrow and over the next few days.

If it's one day it could be anything. But a grumpy baby around this age is probably teething

Is he staring into space? If so he’s probably just tired.

Hi OP here. no he's been like this just since yesterday morning.
actually he just started solids.
and now he has had oats with my breast milk in it.
he's a little lost in himself , not as aggressive and loud as he was just till day before yesterday
thats worrying me.
I wonder if its just because of solid food