body acting weird ? help ???

Hello ! So im 16 years old , and I am sexually active . Although, I haven't had sex in at least 2 weeks .. it is unprotected but my boyfriend always pulls out when he feels himself getting too excited . I was having very bad cramps in my uterus area a couple of days ago and i had VERY VERY light spotting , that I had never had before . Usually my spotting is heavier . I decided to put a tampon in and there wasn't exactly any blood . I'm having all the period symptoms but I see no blood unless I put a tampon in . I was due to get my period this past Sunday and lately my periods are heavy and regular . I'm kind of confused rn , have any of you experienced anything similar ?