You write that you are 5 ft. 8 inches. That you are 18. That you lost 25 lbs over 6 months at 1300 daily. You don't write your current weight or what your gender is. That information does play into the calories needed equation, as does exercise, along with your age. Youths require more fuel than old farts like me.
You write that you weight train 3 times a week...and that you're tired. Your body is trying to tell you something, as is the calories calculation site (or sites) that you visited. I think you are underfed, but that is only my opinion.
You write that you are at a plateau, so no longer losing....maybe your body is hanging onto each and every calorie for dear life because it simply requires MORE to function.
So here is some interesting reading for you - quote:
"At rest (for example, while sitting and watching television), the human body burns only about 12 calories per pound of body weight per day (26 calories per kilogram). That means that if you weigh 150 pounds (68 kg), your body uses only about:
150 X 12 = 1,800 calories per day
Twelve calories per pound per day is a rough estimate -- see How Calories Work for details.
Those 1,800 calories are used to do everything you need to stay alive:
They keep your heart beating and lungs breathing.
They keep your internal organs operating properly.
They keep your brain running.
They keep your body warm.
"The Idea Behind Dieting
Let's imagine that you are overweight
and you would like to lose several excess pounds. To lose 1 pound of fat, what you have to do is burn off 3,500 calories. That is, over a period of time, you have to consume 3,500 calories less than your body needs. There are several ways you can create that deficit. If you assume that you weigh 150 pounds and that your body at rest needs 1,800 calories per day (150 * 12 = 1,800) to live, here are several examples (some realistic, some not):
You could lie in bed and starve yourself. Since you are lying in bed, you are consuming 1,800 calories per day. Since you are starving yourself, you are taking in no calories. That means that, every day, you create a deficit of 1,800 calories and, approximately every two days, you will lose 1 pound of body weight.
You could consume fewer calories than your body needs. For example, you might choose to consume 1,500 calories per day rather than the required 1,800 by controlling what you eat. That creates a 300-calorie deficit every day. That means that approximately every 12 days, you will lose 1 pound of weight (12 days x 300 calories = 3,600 calories).
You could consume 1,800 calories per day and then choose to jog 2 miles (3.2 km) every day. The jogging would burn about 200 calories per day, and over the course of 18 days you would burn about 1 pound of body weight (18 days x 200 calories = 3,600 calories).
You could consume 2,500 calories per day and run 10 miles per day. You will burn 1,800 calories per day at rest and then 1,000 calories per day running, for a total of 2,800 calories. You are consuming 300 calories fewer than you need, so you would lose a pound every 12 days or so (300 calories x 12 days = 3,600 calories).
As you can see from these examples, the only way to lose fat is to consume fewer calories per day than your body needs. For every 3,500 calories that your body takes from its fat reserves, you lose 1 pound (0.45 kg) of body fat. You can create the deficit either by monitoring and restricting your intake of calories, or by exercising, or both.
The idea behind most diets -- everything from Weight Watchers to the grapefruit diet -- is simply to help you somehow lower the number of calories that you consume each day. That's all they do."
OKAY - so you're surviving and losing weight on 1300 daily over 6 months and you're tired and advice on websites is that you need more fuel for your body. You probably do.
For the entire article, visit here: http://recipes.howstuffworks.com/diet.htm
Please diet, and exercise, safely. I am already a little worried for you. It isn't just the quality of the foods you eat (you wrote organic) it is also the quantity necessary for your body to function and to have the energy it requires not only to exercise, but to merely exist.
Maybe the eating disorder history is coming into play here too. Please reach out to someone in real life as well if you need help with that aspect.