While not really equitable in terms of specific circumstances - I was a weird kid in school to the point that people thought I was a potential threat (I wasn't, I'm just autistic).
Get this, I was able to narrow down that the reason they thought that for years was because I didn't talk like a normal human being - so I spent about a year learning how to speak like people I thought were cool, I would find old movie stars, internet comedians, hell even cartoon characters, and steal their vocal mannerisms until I'd created a Frankenstein's monster of a voice to call my own - and people liked it enough that they saw me as "normal" from then on out.
Now I'm not saying it's your voice that's put you in this conundrum - but it's definitely "something" - so I would find and realize what that "something" is that is off-putting to other people and work on trying to make it less off-putting to others - that is, if you wanna go that route.
You could also just ignore it, reputation in school at any level doesn't really translate into anything after school's over - take it from me, I'm 22 and all my classmates are either in jail, out of state, or dead. If you've got a handful of decent buddies, hell more than one - you're in the clear.