My mom told me when i was younger that if you swallow a cherry seed it will grow in your stomach. i am worried about my recent consumption of one i am gaining a lot of weight?

I could not believe you still think what your mom told you when you were young is true. All the seeds that you ate, either digested or defecated in whole. No, you need to limit calories intake and do routine exercise for weight control. At your age, thyroid panel should be checked if you have significant weight gain without change in diet and activity.