I m 24 years old. I ve been feeling some exhaustion and weakness and I have low grade fever. I m a bit pale and have trouble concentrating. I have been feeling this way for about 2 months. About a year ago I had a severe strep throat and experienced some signs of rheumatic fever. I had had a minor dental surgery about 2 months earlier, if that makes any difference. I went to my doctor and had a temperature of 100F, slightly enlarged cervical lymph nodes, and a heart murmur, with abnormal valve sounds. My ears, eyes and throat were clear and I also had clear lungs and there were no significant findings in other systems. He could not tell me what was wrong though, do you have any idea of what it could be?