Help with premed class schedule please. Am I doing too little?

hey everyone! so I'm currently registered for orgo 1, vertebrate anatomy, and two humanities classes that involve a lot of papers. I also plan to work part-time. I switched to pre-med track so most of the classes I have to take are mainly prereqs, upper division bio classes, in addition to psych minor classes (a minor is required in my school).

If I can find any research or volunteer opportunities (although I'm having terrible luck with that), I'd definitely like to do that as well.

Would adding another science like a) genetics or b) molecular and cellular bio class be a bad idea? Or maybe another humanities class (which will also have a lot of writing assignments)? I personally already know I'll be stressed with the 4 I originally mentioned alone lol, but I feel like I'm being "easy" on myself in terms of taking only 4 classes.

For reference, I've been taking 3-4 classes since I came back to school after a few gap years. I'm trying not to burn out since I'm also working full-time at the moment, but I'm also concerned I'll graduate in a million years and won't ever learn to get out my comfort zone. I want to be able to balance more classes and manage my time better. I'm also not sure how it looks to med schools - maybe it comes off like I can't handle a lot? Let me know your thoughts.

Any advice would be really appreciated. Thanks :)