Lost my period, should I be concerned?

I'm not really sure why this could happen outside of a medical reason - I plan on receiving a doctor's advice as soon as I can.

I could have sworn that I was having PMS symptoms right around the time I should have, but then they faded away and my period never came. But all the bloating and other symptoms that come with PMS left, so I feel normal.

I don't think this is because I'm eating too little? If anything, I eat too much. In the past two weeks I've been consuming around 1,700 to 2,000 calories per day as I get closer to my goal. I currently weigh 113 lbs (weighed in this morning) and I'm 5'5.5".

Obviously a doctor's word will be most beneficial, but is there anyone else who has gone through this? Knows why, maybe?

My period has changed since I started to exercise and changed my diet. It is getting closer and lesser, but sometimes I think if maybe I am getting closer to menopause since I am now over 40...better that you go see the doctor, as all women are different when it comes to their hormones...

http://www.active.com/nutrition/articles/nutrition-tips-for-women-with-amenorrhea

http://sportsmedicine.about.com/od/women/a/Amenorrhea.htm

Low body fat and high exercise are typical causes. You may also be lacking nutrients to sustain reproductive function.

I'm not really sure why this could happen outside of a medical reason - I plan on receiving a doctor's advice as soon as I can.
I don't think this is because I'm eating too little? If anything, I eat too much. In the past two weeks I've been consuming around 1,700 to 2,000 calories per day as I get closer to my goal. I currently weigh 113 lbs (weighed in this morning) and I'm 5'5.5".

According to BMI: http://www.shapeup.org/bmi/bmi6.pdf
you should be between 115 - 145 lb. So you're underweight, but not terribly so, so I doubt that your body fat is too low to support having a period. Keep eating the higher calories, good nutrition, reduce your cardio (30 min 3 days a week) and do some sensible weightlifting (as I suggested in another of your threads) and you'll gradually put on some muscle and reach a healthy weight. (And look good.)

I know I gave you that link in one of your other posts, where you thought you were too heavy, and you still have your ticker saying that you want to lose more weight, instead of gaining to be in the healthy BMI range. Hopefully you can discuss your eating disorder with your doctor and get the psych help you need. Even your profile pictures show you as being unhealthfully thin.

The 2 other main reasons not to have a period would be pregnancy and menopause.
If either of those isn't possible, I can't make an educated guess.
(My uneducated guess, not being a doctor, would be a hormone problem or a growth over the mouth of the cervix, like a fibroid. Those are generally not something to worry about, but maybe there is one in just the wrong place?)

ETA: I forgot stress. With all you're doing to abuse your body, even though you're not terribly underweight yet that could definitely do it - eating too little, exercising too much, trying to lose too much weight (instead of gaining so you're in a healthy range).

Well this is a regular process of having an eating disorder. I recall you posting about it a few times, and still wanting to lose weight/cut more calories and/or over exercising.

So yes, you should be concerned - though not surprised.