I always find that starting any new job is exhausting! There is so much to learn - not even the “work” itself, but processes, personalities, and systems that differ from workplace to workplace. Unless you are struggling hard financially, give yourself some time. For me, it takes at least 4-6 months in a new job to feel ready to add something else. (Now that I own my own business, it’s just adding the next thing in the business…then 4-6 months later, the next thing…). You will have to feel out your own balance and where you can draw the line. I don’t think it’s a bad idea to make more money, if that’s a goal. But you can’t do it at the expense of your sanity, relationships, health, etc. Make it sustainable.
I’m in the US for context, but have lived all over the world, and don’t participate in the hustle culture here. I work hard for my clients and there are crunch times, but on average it’s about 30-35 hours a week. That’s a sweet spot for me! I hope you find yours.