My daughter has been unwell the past few weeks. She has been very tired, is throwing up occasionally with a high fever, having blood noses, has sore joints and seems to bruise easily. I am very concerned and have taken her to two different doctors but nothing has been done, and I don't know what she needs. I am very concerned for her health. Please, what may be wrong with her and what do you recommend I do?

Keep going to doctors until you find one who will listen and preform proper testing.
If an emergency happens (a fever over 104, bleeding that won't stop in 5 minutes, and such) go to the ER.

This is one of those instances that I rarely suggest. Please take her to the ER, she needs to be seen by someone who specializes in acute care of multiple symptoms. The bleeding and the bruising has me concerned.