What's normal? Well, as Curmudgeon said, it's entirely subjective. You'll find differences in every area you're in, but a few staple things tend to define "weird" people in our society from a social standpoint, especially in high school. You may be considered "weird" if you display some of the following traits:
You are reclusive, tending to keep to yourself either because you are afraid of what others might think of you when you socialize them or you have no idea what to say or dislike being around people. This is true of in-school situations as well as tending not to hang out with people after school, except for those that display similar traits on this list like you.
You tend to be a sort of "obsessive" nerd. You talk about video games a lot or express that you really love the internet or video games. A lot of people will consider you weird if you enjoy franchises such as Zelda or some other franchises, though this is not exclusively a trait that makes many people weird and depends on the area - people around here don't have problems with that unless they have reason to think you're a simple recluse who plays video games more than even thinks about socializing.
You have a desire to be an extrovert and fit in with people, but don't know how to do it. A lot of times this makes you relatively reserved, especially if you've been that way for your whole life. It may be hard to integrate into a social environment once your "rank" has been established. People can consider you weird if you're not within their social hierarchy.
You could be considered weird for dressing weird - this means not following standard fashion styles. If you don't care about the way you look and have ratty, messy hair a lot of people could consider you very weird, especially if you display one or more of the traits on this list. People will tend to not want to socialize with you because you seem like a "weird downer" because you don't visually care about how you look. Regardless of what you think on the inside, people react to how you reflect your feelings on the outside and judge you based on this.
You could be really into some things like anime, cosplay, spending large amounts of money on unnatural hobbies. This will seem weird to a large majority of people since only a minority actually participate in these types of leisure activities.
You may speak funny; your vocabulary might be odd or you may be hesitant when you're speaking because you aren't a socialite. A lot of people will consider you weird if you don't like to respond to people very vocally at all or can't carry a conversation.
It's not easy to get out of a funk and get people to change their opinion of you. I'd say more often than not it's because you didn't deem socializing an absolute priority early on and just took it as it came. This can get you really mixed up in the social hierarchy and simply react based on where you end up. It can be hard to change where people position you in society, but it isn't totally impossible. Extracurricular activities and sports help integrate people into different social classes as a rule - you begin to interact and perhaps become comfortable around different people. It all depends on your preferences as well. If you don't like to be considered weird by people but also don't wish to integrate into their social hierarchy, you should rethink how you consider your self-esteem. You could cause some large problems for yourself with over-contemplation of meaningless nothings.
I integrated into a purely popular social hierarchy in the latter half of high school. It isn't exceptionally hard but it isn't exceptionally easy. Many people likely think you are reclusive and have some weird hobbies and just don't like to do a lot of the things that other people might do - go snowboarding, hang out and play Call of Duty, or whatever else people around your area may do regularly. You aren't in on their jokes and you don't know their personalities, so it's hard to be comfortable around them and it's hard for them to be comfortable around you. The best way to get people to kick the "weird" representation of you is to change some of the things about you - of course, if you don't really want to, you don't have to change anything about yourself. It's also very likely you're just trapped into a social class that doesn't truly represent how you'd like to be, in which case you should feel free about changing some things that might currently define you on the outside. Any way to become regularly associated with a group of perhaps more "popular" people in your local society is a good boost to the opportunities you have for sociability and getting rid of the definition that lingers around you.