This is not quite the same as a full breakdown, it sounds more like a burnout. Which is still important and a lot of people will relate with, including myself. Part of it (i.e. as long as it doesn't affect your life experience in a disproportionate way) is also very normal -- we all wander what's the meaning of our life.

Searching around for burnout, including on this website, might give you some relatable stuff to read. It's possible that solving it might require you taking a long break (if you can), or reevaluate your life and change careers. These are things that take courage however, and a lot of people just keep going because they hate it, but it's still their comfort zone. Give yourself time to mature a decision, might be a few years, even.