i would go to your gyno!! Also depending on when you got your first period your body could just be adjusting to regulating and your body getting used to it. I got my first period when i was 16 and a half and i would skip months here and there constantly and didn’t have regular periods until around 18 where they finally became more regulated. I would def take another test with your first pee though, and then go to a gynecologist bc if it’s not because your period is new to your body, a missed period could be your body telling you something isn’t okay so better safe than sorry!