I had been working to lose weight, for over a year. I'm not trying to any longer, but considering the amount of exercise I do and the calorie restriction for so long, I'm pretty sure my metabolism is a little off. I don't see how eating 1700-1800 calories when I burn 1000 or more five days a week can be enough.
I know that depressed exercise heart rate and super-rapid recovery time are symptoms of parasympathetic over training, which occurs after sympathetic over training is ignored for long enough. And as I am stubborn about my exercise routine, I have ignored signs of the latter, such as unhealing injuries, persistent fatigue, etc.
I haven't gotten my period in about 4 months either, and pregnancy is off the table.
So all evidence points to a body that isn't getting the resources, i.e. calories, it needs. I don't think I need to take more rest, as I take two days off of exercise a week and that seems pretty reasonable. With that in mind, I ask again about how many I should be eating, maybe how I should go about adding them. Macronutrient advice is welcome, but the bottom line is going to be energy intake.
Calorie indicators are a generalization, a starting point, but not what you in particular need. If you're not losing weight, you're not eating too little. Pretty simple. But the quality of your food might not be just right, or the time of eating, which can account for some of the pain. For example, after running, if you don't cool down and then stretch, lactic acid will build up and cause pain. High antioxidant foods such as berries and colored vegetables help control lactic acid build-up. As you can see, if you're going to be on such a high output exercise program, you'll need to learn more about nutrition. The other thing is proper body movement -- if you're moving wrong, you can end up with problems down the road -- that's what athletic trainers are (theoretically) for. And running is a high impact activity. If you run, play basketball or football or soccer, you know, anything high impact, eventually many people are going to hurt and injure something. It's a balancing process of how much someone gets out of the activity vs. what it does to the body. As for heart rate, the more you exercise, the slower your heart rate will be. That's a good thing -- that means your heart has gotten stronger. I've been exercising forever, and it's really hard to maintain a high heart rate because my body just slows it down, it's used to exercising, but that also means I have no blood pressure problems and the like. I do, on the other hand, have a lot of injuries now that I'm in my fifties, so there you have it. I'm healthy in my organs, but my body needs a lot of fixing. For example, I just learned in physical therapy I virtually have never used my glutes. I've done martial arts, running, basketball, bicycling, and weight lifting and I have no strength whatsoever in my glutes. That's what I mean by learning later you're exercising incorrectly.
If you will look at the Nutrition Facts Label on any box of cereal or bread pieces, the calories burn are based on a 2000 to 2500 calorie diet per day. You are very near the average number of calories used based on an active diet. Add a piece of cheesecake to your diet, and you should hit the weight scales just right.