Is 900 calories a day safe for me?

Hi everyone. So i am 5"6' and 188 pounds. I have been loosing weight slowly this year, 20 pounds so far, but that is because loosing weight during a school year is so difficult. But lately, i have been eating, im guessing around 900 calories a day, and working out for about an hour to an hour and a half each day. But i eat things like Oatmeal, yogurt, cheese sticks, and fiber bars. i eat 1 thing every 2ish hours to try and boost my metabolism. and water. But is this 900 cals a day safe for me? or should i up it? im trying not to eat any carbs either... i splurged tho tonight with a bowl of rice but What evs. Thanks :)