Should I get a humanities degree or a legal studies degree?

Degrees like humanities and women's studies aren't designed to prepare you for a specific job.  It's not to say that you can't get a job with those degrees, but those don't line up well with particular jobs like nursing, teaching, and engineering degrees might.  You acquire a lot of valuable skills with those degrees - writing, communication, critical analysis, etc.  Those skills are useful in many fields, and so those degrees might help you get a job where you just need "a degree," and not a particular one.  If you wanted to teach with that degree, you'd have to go to graduate school.  Unfortunately, humanities fields are being cut from some universities (mine included), so the job market there isn't going to be great in coming years. 

Legal studies can be different things at different places.  At some it's more of a pre-law program and you'd probably have to go to law school to turn it into much.  It might prepare you for a legal secretary position.  In other places, it provides the training necessary to be a paralegal, which can be a very good career.

I am an adjunct professor/lecturer teaching 23 hours a week making $109,000 a year from it.  That’s not exactly a small sum for relatively little work. 

Either one is going to require grad school for you to do anything with it. Both of those degrees are preparatory degrees for further study. So you have to decide, "Do I want to be a college professor, or do I want to be a lawyer?" It's as simple as that.

By the way, college professors aren't as underpaid as you seem to think. The salary is substantial enough, especially if you supplement your income by writing your own textbook that you require your students to buy, for you to live a very comfortable middle-class lifestyle. What's more, lawyer incomes aren't as high as you might think. It's not like it is on TV. Unless you move to some huge city where you can work in corporate law, you're looking at starting out with a five figure income that at some point may work into a low six figure income. A middle-America professor and a middle-America lawyer earn comparably. Of course, it will take you somewhat longer to become a professor, but if that's where your heart lies, if that's what you enjoy, if it's the humanities that pique your interest and not law, which is reading but is pretty dry reading unless the intricacies of logic and debate are what pique your interest, it's worth the extra few years to get there.

So your question of what "should" you do depends entirely on you, on what interests you. For most people, the choice is very much six of one, half a dozen of the other as far as lifelong income goes.