When you open “next episode” before you have really decided to, you are 上头. In everyday online Chinese, it means that a person, show, game, or feeling has pulled you in so hard that your impulse is getting ahead of your judgment. The word often carries a little self-recognition: you know you are overdoing it, and saying so with a smile is part of the point.
That makes 这部剧太上头了 stronger than “I like this show,” and 我好像有点上头了 more than “I have a crush.” The feeling has started to steer your attention and choices. 上头 also keeps an older alcohol sense in 这酒有点上头: there the drink is physically hitting someone, not making them infatuated. When friends are talking about a person or something they cannot stop following, the modern figurative meaning is the one to hear.
