What Causes Loose Stools, Fever And Breathlessness?

I am a girl with age 18. I am suffering through a number of physical issues since two years. At first, it all started from sudden loosemotions. I often got admitted in hospital for this reason only. I visited many reputated doctors but none of them was able to reach any conclusion. At last I was declared celiac, however it wasn t the case. Suddenly without any medications my loosemotions stopped. It was weird but I was relieved but soon after 2-3 days my right chest started hurting alot. I couldn t walk, breathe, sleep. I got xray done and it revealed that I had pleural effusion in my right side of chest. Doc took out 20ml of urine coloured liquid and sent it for lab testing. My ADA was high but malignant cells were not present. So the doctor reached to the conclusion that I have closed TB. I took the TB medicines for 4 months. I had very ups and downs in my in those months and suffered through loosemotions often. I changed my doc for second opinion. He said that i Have major swelling in my lungs and it can get worse if i inhale air pollutants as I was allergic to smoke and dust. He told me to get a good amount of rest and not to climb stairs or walk much. At first I daily had mild temperatures and had shortness of breath the whole day. I thought I was getting better but one day suddenly my ankles, upper area of foot, side and back of knees, front of elbow, my back, started aching badly. I suffered through this pain for days as I thought it was normal body pain but the pain got worse. I had severe weakness and often had floaters in my vision. I also lost alot of weight and now I am underweight. 42 kg with a height of 5 4. I couldn t walk or climb stairs my feet trembled alot with tremendous pain. It was as if I am not in my senses. I had eye infection. Small pimple like things all over my shoulder and back. My breathing problems got worse. I visited my doctor. He said my lungs are getting worse day by day and a certain disease ( i don t know what it is) will get activated if I push myself hard. He also said that i can t continue my studies this year. I only have to rest properly however he said that i can walk until I face any abnormalities in my breath. But I can t walk for 5-6 minutes without taking rest. Then that means I can only wander in my house a little. Its just ruining my life. I can t understand what s this all about. What s the exact issue with my body?