Has anyone ever been so jealous of you? If so, why would that be?

Yes

I wrote a short novel (not published) a few years ago. A guy I know claimed, "I helped him write it." (Of course, he didn't; I got no help from anybody.) He insisted he did, to the point of being psychotic.

Instead of "wishing" for something, I've always gone out and done it or got it. A lot of people are unable to grasp this concept. When they don't have the experiences or the possessions I have, they express a lot of jealousy. I think they expect everything to be given to them without any effort on their part. I find it to be very petty of them.

Yes, I’ve had people look at me and say they’d like to be thin like me. They also think (incorrectly) that I’m naturally thin. It’s actually my low-carb diet, not luck.

they just try to get what you have

Yes. I'm currently sharing with a narcissist. They need constant praise and want everyone to idolise them. This narcissist doesn't get the praise and adulation they crave from me so they watch everything about me like what I wear, what food I eat etc. as though they see me as competition. Then they humiliate me to others at given opportunities to make me look like a lesser person than themselves.

Jealous of me? Why?