Been there. This is hard to see right now because it's all you've been exposed to, but the microcosm that is high school is such an insignificant part of your life that you'll forget about much sooner than you think. For the bullies and "cool crowd" that like to think they're better than everyone, this is the best part of their life. Once you graduate, reality sets in. Those people generally don't make it very far because instead of building a foundation of tools to succeed in life (e.g. disciplined reading, sound math skills, critical thinking, and problem solving), they're distracted by the need to climb to the top of this small social bubble that eventually bursts on graduation day.
Life is not like high school. Unlike kids who never study and are simply pushed through the educational system, people who don't try hard in life struggle to get by. Society doesn't need people to look cool (there's a surplus of that). It needs people who excel at things to advance society. People who fill the needs of society profit. The people who prosper are generally intelligent, talented, or both. Oh, and if you've slacked a bit so far, it's never too late to start building this foundation for yourself. Luckily, you won't have the same fruitless distractions those kids have.
College is a lot like life, because people organize themselves into groups according to their talents. Logical people become science or math majors. Extroverts become business majors. Artistic people become arts majors. People who excel are rewarded for their achievements (academic awards, scholarships, internships, professional networking). Those who fail do not graduate.
And because of the nature of college, people generally treat each other with respect. This not only goes between students, but for student-professor relationships as well. And because you're treated like an adult, there's people there to help you like an adult. If you are struggling with depression or social anxiety, there are student-life staff who will listen and talk with you. They genuinely care. This is much more the case in college than in high school.
Smart people are sexy. Smart people are in college. You'll have much more intimate relationships with people who can engage you in enthralling conversation than with airheads. Smart people are more approachable because they're more down-to-earth. Sign up for activities in college that might seem stupid at first just to meet people. Go in without any expectations, don't put any pressure on yourself, be nice, make friends, and yes, you will get laid sooner or later.
Yes, things will improve after high school, without question. Don't be hard on yourself, and do the things that make you happy without worrying about what anyone thinks.
P.S. the REALLY funny part is that as you get older, usually you see the attractive kids get fat and ugly, and the "ugly ducklings" turn out to be fit and good-looking. My theory is because the latter typically learn how to prioritize the things of substance in their life (such as health and life-long learning), as opposed to falling prey to addictions and lack of motivation.
It is impossible to enjoy idling thoroughly unless one has plenty of work to do. -- Jerome Klapka Jerome