The main reason that I don’t think he’s pretending to like you just as a prank or something is….that’s not something that people do, generally speaking. It’s just more elaborate than what the average teenage boy is going to do.
As for your second question “is there anyway where i can stop being so weird around him?”, well, no. But you can gain a better understanding of what it is that is causing you to act weird. Basically, when we act “weird” or in a way that we find embarrassing or not how we want ourselves to behave, usually there’s a triggering even where something has played out in a way that’s unexpected, and we weren’t prepared for how to react. In this instance, your previously expected him to act one way to you, and now he’s acting a different weird. Unexpected behavior from him leads to unexpected behavior from you.
One other thing to keep in mind: no one thinks your as weird as you do. No one is watching us constantly or aware of all of our own weird little quirks except ourselves. So cut yourself some slack.