Is my calorie intake too low?

Yeah. I think it is, but everyone is different so you will hear different things from everyone.

My advice is play around until you find what works for you. I'm 5' too and try not to get below 1300. I really don't think it is healthy to go below your BMR (http://www.bmi-calculator.net/bmr-calculator/) without medical consultation.

You can try and find your TDEE and eat 20% below it http://www.fitnessfrog.com/calculators/tdee-calculator.html

Anyways.. the 1200 calories a day can become a bit of a debate on these forums. Some swear by it and others can't tear it down enough. Just play around and listen to your body until you find what works for you.

http://www.myfitnesspal.com/topics/show/952996-level-obstacles-lose-weight-target-fat-easy

In my opinion you do need to be eating more. You should be going for losing no more than a pound a week.

The key thing with what you are experiencing is your metabolism is in starvation mode. This means that your body will store weight instead of burn it.

What I recommend and have used to lose weight without exercising, try eating every 2-3 hours about 150 calories. Do this until about 30 minutes before you sleep. This will jump start your metabolism because your cells will have all the nutrients they need to function properly. It will take from 4 to 21 days for this type of eating to take effect and increase your metabolism.

The 2000 calories a day is necessary for cell metabolism, less than that regardless you height, you are starving you cells. For your height and weight you should consume about 1600 calories per day, especially if you walk daily.

One thing I notice about myfitnesspal is that it starves you, which is not good. So of course in the beginning people lose weight then plateau and get no more results because the body does not have enough to properly function. 1200 or less per day is considered a form anorexia.

Yes im a science and nutrition nerd and yes its not easy.