Question about being on birth control short-term

Hey ladies, so I was put on birth control for about a week and a half to prep by body for my uterine septum removal surgery this past Tuesday. I recovered pretty easily and stopped bleeding after about a day (it was really only spotting). Then after a day of no bleeding I started bleeding a lot heavier (almost like a period). My question is could this just be my period coming early since I stopped the birth control or would it be just a delayed bleed from my surgery? I guess I’m asking if it’s possible to have birth control change your period to come so early when you were only on it for a short time. Thanks so much for anything anyone can share!