Jealousy

Hi, I’ve been kinda jealous lately Bc I saw that my bf’s new Instagram account he follows and girls follow him and stuff which is fine but I saw this girl that he went to school with but he never really liked that he follows her and liked her most recent pic which was a bikini pic with a close up of her upper body showing her boobs (they’re pretty big) . Idk if I’m being like waaay too jealous but it’s just something I’m feeling and also since I’m very insecure about my boobs it just kinda tripped me up, is this normal? What should I do? Is it my period?🤣