Does my crush like me back or is he messing with me?

okay,so I've had a crush on this guy for months now. he's in a different class entirely and we have never talked. I've made it EXTREMELY obvious that I liked him and he started to look back at me,even when I'm not looking. there has been incidents like his friend group whistled at me outside of school and he told them to stop,his best friend saw me and yelled my crushes name and told people to call him over (my crush wasn't there),he followed me around school once,he sometimes tries to get phsyically close to me. But I'm not a very social person and he is quite social and comfortable and he has many friends,so I don't understand if they're mocking me or he actually likes me back. he has many friend groups and also very close female friends. all I know is he has never had a girl friend and he is single now,but he was talking with a girl with his elbow resting on her shoulder and stuff. and he liked another friend of his entire Instagram posts. I assumed they both are just his friends and he isn't interested in them but my friend said that that kind of behaviour is not okay and I should move on. I don't understand whether or not he's mocking me or he is genuinely interested,one thing that weirded me out is one time I was walking down the stairs and he was walking down next to me,I didn't know it was him so I turned my head towards him to see who it was and he sped up and practically ran away. but next week he did the same thing to me,I was walking up the stairs this time and I was tugging one of my friends along (I was walking faster than them so the friend I was tugging along was behind me and another one of my friends were next to her.) appereantly he sped up and walked past them and slowed down when he came next to me,and got so close we were practically touching. we appereantly walked up to stairs next to eachother and I somehow had no idea this happened. this is extremely confusing for me because I don't know if he's playing some joke on me and he is interested in other girls or me. could this be just mocking or is he actually interested in me?