Worrying a lot about bullies or judgemental people, pls help

This is my first post here, and i'm really sad because this is something that i'm always thinking about, and it's so hard for me to let go of the worry. I had a bad experience in my first few semesters of university. I thought i was starting to feel better and less anxious, but when i didnt expect it, this one girl in my class started talking about me for no reason at all. Everyone in that class was pretty quiet, and i just minded my own business. I always looked to the front of me, so i never even noticed her (she sat more to the side). I thought things were going fine, until one day she made a remark about me concerning a recent exam we had. I never spoke with her or anything, so in my head i thought it was so rude of her right away. I started to tear up because i couldn't understand why she'd say something like that. It was in a very rude tone! I let it go, but in the next few weeks, everytime i spoke in class or read something (only when the teacher asked), she'd whisper and snicker. Then one day she came up to me out of nowhere, and gave me a very strange look. I was already very anxious because of personal things, but dealing with her made things worst. This happened a good while ago, but it still hurts me when i remember it. The next semester it happened again with two random people in another class. I guess i just need some advice for being less anxious about these things.

The problem is, people like to say that they get bad vibes from ppl. Then i start to worry that it's all my fault because i gave out a weird vibe? That makes me even more anxious because then i feel like i cant control it . Please help me, thank you.

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Just remember they're no better than you so try not to put yourself down and if she gives you a dirty look glare at them or give a dirty look right back 8)
next time SHES asked to read whisper something like "skank" or "omg is that bad smell cuming from you!!" put her off and give her a taste of her own medicine. wen she sits down go "if u whisper rude things to me ill do the same to you, see how you like that bitch!" little over the top but i really hate people like that. go for it!!

This girl is probably insecure and jealous of you.

Maybe two ways of seeing it.
She does it as she knows she is getting a reaction out of you.
Or, alternatively, she does it as she wants to know you but you're presenting a load of antisocial vibes caught up in your own anxiety and that.

Second one is interesting as I just randomly thought of that?

Some times the biggest offense to some people is not being acknowledged or being ignored. Maybe she felt this way and got sick of it and lashed out?

Maybe she's mentally ill? Whatever that is, just think of her as mentally ill...
If you did nothing wrong, there's no need to worry about it...there are always stupid people out there..
even if you have ever done anything to her, I don't think you need to feel sorry...because what she has done made you suffer enough. Plus she just sounded totally retarded...ignore retards...
I got sworn by totally random people on the street...on the train...even in supermarkets...just mainly because i belong to an underprivileged group...at first i kept asking myself if i had done anything wrong...or if i can change myself to avoid similar situations...but gradually i realized sometimes i just cant change how people view others in their eyes...and one day, after I got sworn by some random jerks, I talked back to them. Then they didn't say anything to me and ran away...I didn't swear at them or anything...and physically I am pretty small...some people are big talkers...and when you actually "talk" to them, they turn dumb. Maybe if that ever happens again, you can confront that weirdo?