just need some help

so basically me and my boyfriend broke up recently☹️ i've been feeling really down n i'm not missing him at all, cause i felt like this when i was with him so it's something to do with my body! it's really hard cause at school my friends take the piss n say i'm missing my ex so i get like bit arsy n get abit down! i'm due on my period n it's like 9days late what's wrong with me help!!! ☹️