What Causes Extreme Fatigue In A Child?

My daughter who is 3, she will get up still tired and looks tired she will play for 5 -10 minutes and need to sit down. Then she will fall asleep, you can t keep her awake. She is always looking pale. Also she has had a continuous for 5 weeks, had a cough for just over 3 weeks, had a urinary tract infection she was on antibiotics for 2 weeks,complaining of really bad joint pain and a headache every day, she doesn t like light. she had severe conjunctivitis we tried 4 eye drops but they never worked so she had to go on oral antibiotics. She s been of the antibiotics for over 24 hours now and the conjunctivitis is coming back, i think the water infection, and she now has thrush. Could you help me with what it could be please? Thank you. Roxie