Clearly your parents have some reason for thinking that the gap year would be a bad idea. They're not making that reason apparent and it's pretty important that they do, because it just seems to you that they're forcing you to be miserable just because. If you understood their reasoning, you might change your perspective.

It's possible that they're simply afraid that you'll get your hand stuck in the monkey trap. You'll get an apartment, meet someone, get a loan for a car and the BOOM! Now you suddenly have too many obligations to go back to school and that gap year turns into 2, then 3, then 4.... And that happens all the time. There are millions of people who never finish college just because of a handful of credits. They fail the courses, or miss a semester and think, "I'll get that done soon; maybe night courses, or as soon as I get ahead with some money." Then they never do.

If that's the reason, you could come to some sort of compromise. Tell your parents you're really unhappy with your law school options and it's really affecting you. So, you want to dedicate yourself to study. In order to do that you'll need to have a reasonable plan. You'll stay at home, study, and maybe take a couple courses at community college to ensure you remain academically active.

But, it's possible that your parents are just controlling, or unhappy with their paths in life and want to push you into their vision of your happiness. What they envision might not be what you want, and that's going to create quite a lot of friction for years or decades to come. You have to sit them down and really explain that what they're asking you to do is making you unhappy and is killing you enthusiasm.

Or they might have some other reason entirely. Whatever it is, you need to dig that reason out of them and explain why that isn't for you. But, you'll also need to find that compromise.

Right now you're just butting heads. And sometimes that's the easy way. It can be tough to confront your parents and really dig at their motivations, because you're used to being a kid and having the kid/adult relationship. But, now you need to have an intimate and personal discussion with them, and that's weird. That's okay. But you need to get at their motivations without bumping heads, because you can't have a shouting match, but need a calm and reasoned debate and a calm and reasoned compromise to the situation.