Trying to lose weight safely

Patient: I’m trying to lose weight and I don’t know how many calories to eat. I’m 15 and weigh 152 my height is 5″ 7 and I do cardio for about 30 minutes. And im eating about 1200-1500 a day. I feel like its a problem because I feel tired and light headed when I work out.

Symptoms: Dizzy,weak,ligh headed