F16, need advice to loose 50 pounds with a school schedule😭

Im 16, 203 pounds, and im 5'5. I need to loose 50 pounds but not sure how. I go to school Monday through Friday and dont eat breakfast or pack myself lunches. When It comes to eating ill get the schools crackers and cereal and ill eat that throught the day and then ill eat dinner. Sometimes ill find myself eating more unhealthy snacks like bags of spicy chips or honey buns because my boyfriend will buy me stuff. On the weekend ill find myself eating alot of small things that add up big time. What can I do to fit a schedule of school from 7am-4pm? Any advice from people who also have a school schedule?