I dont understand how much calories im suppose to eat to lose weight?

I'm male 22 and weigh 188 lbs. I wake up at noon everyday and make three egg whites on two slices of natures own whole grain bread with a glass of chocolate milk. And around three or four pm I make a bowl of non buttered popcorn. Then at seven or eight pm I eat a chicken breast with mixed veggies or brown rice. Then I run for thirty mins. At midnight I drink a glass of chocolate milk and sometimes eat a lean ham and cheese hot pocket. Then I go to sleep. I've done this for a week and a half everyday and lost 10 lbs. Now is this routine gonna stop me from losing weight down the road? And is it unhealthy? If it is why is it unhealthy? And I don't want to make myself eat more for no reason.