Why did my crush act this way?

there is this guy that i have a crush on i m not sure how he feels about me though.

he started a conversation with me, we held eye contact and at those moments i could feel we were both into each other but after that, he started acting weird.and that s what s confusing me.

-i went up to him and said hi and he seemed a bit nervous although tried to act cool. (he avoided eye contact) i asked him what class he has now? and he said he has a lab, and i was like oh yeah i had my lab too, then he said, no i mean i have a tutorial.

-again when i was talking to him, he was constantly looking around avoiding eye contact, when he looked at me though he said yeah, so i ll see u in 3 mins? no, what am i saying, i mean 3 hours?

-he asked how my presentation was and i was like uh, i was nearly fainting, then his face changed like he actually believed i fainted and he looked angry until i told him i didn't actually faint, i felt like i was fainting (he knows english isn't my first language) and so he was acting all serious with me

i know he doesn't hate me, cause he always says hi when he sees me even when i don't notice him and he chose to sat next to me instead of his friend in one of the classes we had so why is he acting this way?

he has lots of female friends that he is so comfortable with and he jokes around them all the time :(