Please tell me if this is healthy?!?

HI, I'm a 13 year old boy (using moms account) And i've lost like 75 lbs in the last 4-5 months. OK, So i found this new breakfast routine ADDICTING! I eat a BIG bowl of cornflakes with cut up strawberries and bananas with skim milk. For lunch I had a bowel of cut up strawberries, apple (not whole) and some gs with skim milk and I also had for lunch one sloppy joe (which 80% lean ground beef) on 100% whole wheat bread with some veges. (peas and carrots, canned) Will I gain weight??!? I work out everyday i'm terrified about gain weight! HELP!?!?!