Baby wants to be held allll day

My month and half year old wouldn’t let me put him down today and I mean all day. Hes had days like this before but never this clingy. I have to lay down with him and put our foreheads together to get him to calm down. Why do babies have days like this? It’s currently almost midnight and this mama has to get some sleep. Any advice?

And I know babies need comfort and I’m doing my best for him but moms need sleep too