Is it normal to miss your period...

Uhh, only eatong 900 calories is horrible for you. you should be eating 1800-2000 calories. or 1400-1800 to lose weight.

Nope, you are preggers.

Your period might be irregular. I know I've gone a month or two without getting my period.

It's possible to have irregular periods or even miss one without being pregnant, however you should be careful with your diet. Calories alone aren't enough to judge how health a diet is, just make sure it's balanced, take a multivitamin and ask to see a nutritionalist who can help you lose weight while making sure your body gets everything it needs. A good diet can do wonders for your skin and hair so it may be worth looking into.

Its normal if youve cut your calorific intake by that much but it means you are extremely unhealthy and yes, you should be worried. Go see a doctor asap

if you suddenly changed your food habits , it can lead you to miss your period because you should lose weight slowly and give your body the time to get used to this alteration... go to a dietist and ask him for a correct diet

Take a pregnancy test, dropping calories shouldn't stop your period

It's normal. But I'm sure 900 calories a day isn't normal. Did you talk to your doctor about this? If not you need to go see him. ASAP. It's not healthy.