Ladies I m watching my 3 year old has suddenly started being very emotional

The other day he was crying silently while going to sleep I asked why he never answered and said want to watch washing machine ( his obsession these days) now he is crying with the drop of a pin I m very anxious with this behaviour just don't know when, where and how will he throw tantrums this has been very recent.. silent crying and he is very happy talking and suddenly he might think of something in his mind and Starts crying..today he woke up crying saying I want to go to park..then he wasn't settling all he wanted was screen time