Hiding phone a red flag?

I was cooking and turned to watch what our son was doing, my husband looked at me out of the corner of his eye thought I was looking at him and immediately turned his phone to the side then quickly flicked to something else. He also recently asked me to lend him money which I have no problem with but he's been working crazy long hours lately, going in early/coming home late and when I mentioned this he said he's actually been doing half days or having 3/4 hour breaks but staying at work. Am I being irrational to wonder why he hasn't mentioned this untill now? We have a small baby at home that I would think he would like to spend time with for all the firsts. It's not to do with a Christmas present as he isn't a big gift giver (we've been together years and he always gives chocs or perfume)

He's constantly on his phone and getting messages at odd hours coupled with not having any interest in sex which is out of character for him. What do you think?