Sprintec and weight gain

Okay soo I’ve always been a very small girl. I got on sprintec back in September and since then I’ve steadily gained weight. Like 15 pounds at least. It’s really freaking me out bc I’ve never dealt with weight gain, in high school I was honestly probably too small. Anyways I’m just really nervous that I’m going to keep gaining and not be able to get it off. I try to eat right and also work out and it’s like nothing helps I keep gaining. HELP