What could it be? loss of appetite, diarrhea, 3 week long period......

For some reason, you are exhausted. You are sick for sure and on those occasions, it is very hard to tell why this happens and how long should period last. Generally, your stool is 60 to 90 percent water, and diarrhea can cause significant fluid loss and stomach cramping, which can lead to your stomach issue as well. Diarrhea can also lead to loss of appetite, which is totally normal. Have you tried to treat diarrhea at home? You know, to eat what you need to eat and to avoid foods that can even make it worse? Also, maybe because your organism is fighting something, you are way worse and you are exhausted more since you are at your period. It requires medical care, for sure. 

You are tired and thirsty because of the diarrhea, there is no doubt there - diarrhea causes you to dehydrate and major signs og dehydration are both constant thirst and tiredness. For how long has this been going on? Are you taking any kind of medications or anything? How is your appetite? The best thing you can do right now is to go and see a doctor as soon as you can, these kind of symptoms will exhaust your body to its limits and you really do need to find out what is behind this.

its been a month or more now

i went to the doctor first time and got a blood test and he said there was nothing wrong but when i said i've had my period for 3 weeks he said to do another blood test and chest xray which i just got done today. i was just hoping someone had some idea before i go to the doctor again next week

What was the result??