I'm going to chime in here a little late to echo what I think the other posters have been trying to convey to you, essentially if I could only give you one piece of advice it would be to stop focusing all your energy on what happens if you fail, learn to have more confidence in yourself and just go work as hard as you can to get to where you need to be. There are hundreds of people in the same boat as you grades wise, applying to law school, who end up getting into law school because of great LSAT scores, getting fantastic work experience, etc. so don't write law school out of your future just because your grades aren't perfect right now.
If you consistently focus on how you can't get somewhere, or what happens if you don't get somewhere you aren't going to get there, it's that simple. Stop focusing all of your energy on multiple alternatives. I'm not saying having a backup plan is a bad idea, but a backup plan is something that you start focusing on once your Plan A fails, you aren't at that point yet, so focus your energy on doing what needs to be done for your plan A (law school) and worry about your plan B (paralegal/ whatever) if Plan A doesn't end up working. Basically, don't put the cart before the horse, you haven't failed to get into law school yet so don't act as if you have.
As far as taking an extra year goes if the only think holding you back from doing it is worrying about how a law school views it, then don't worry, for the most part they don't care. In addition there are several schools that consider your best x amount of credits, or your best two years, regardless of how many years it took you, so this could be a great option for you, one that I think you should really look into, regardless of whether or not you take an extra year.
I suspect that you already know the answer to when you want to/ should graduate. If your main focus is getting into law school, and you need to improve your grades to do that, then choose whatever path will give you the best possibility of doing that. However if you are still not 100% that you want to go to law school (which is fine!) and your main focus is instead to please your parents / graduate as close to on time as possible, then the choice is again pretty clear.
Whatever you choose to do, good luck. Don't forget that you don't need to have the next 50 years of your life planned out now. You're still young, you have plenty of time to figure out what you're going to do when you're older, and if you look around you'll find that the majority of people around you have no idea exactly what their future holds either