Two year old has been crying so much lately

I have a 3 week old and I’m convinced it’s because I’m showing him more attention, she was the only child for almost 2 years . It didn’t start soon as he was born it started about a week ago . She wants picked up and when someone tell her no she cry , she wants to watch YouTube she cries, she’s literally crying right now as I type this. We are watching the bre movie right now and she’ll bust out whining then stop. I’m give her attention , well I try. It’s kind of hard when I’m the only parent right now. Any advice?