4 month old always screaming for attention help!

Hi everyone

My 4 month old just screams for attention and it's weird because I am trying really hard to give him everything he needs but he is constantly screaming (not crying just screaming really loud) and to me it feels like he does it on purpose becuase if I look at him he starts smiling.

I don't know what to do. He has no interest in his toys and he never wants to play on his mat he just wants me to pick him up or talk to him.

I am a first time mum and I am losing my head trying to see what he wants but I really just don't seem to understand

Any advice on how I can entertain him without over tiring myself?