Well, first, I don't think it's a bad look, it should make you a little proud to have that reputation and it makes sense that you want to maintain it, which can take effort. Don't put too much pressure on yourself though, because I don't think it's worth it in the long run (mental health issues vs. the little reward one gets later in life for getting slightly better grades).
But also, could it be that this has become an important part of your identity, perhaps even the only thing people remember you for? I was in that situation as well, always labelled as "the intelligent one" or "the nerd", which was very annoying... but when I got surrounded by many people more similar to me, I lost the label and it actually hurt. It felt like I was nobody anymore, I had nothing unique that made me "me". (In the end though, it allowed me to discover all my other personality traits

).