My 2 1/2 year old son has been limping for 11 days now. We has been to the doctor to rule out fractures, viruses, lyme disease, etc. However, he is not getting any better. He can't/won't put any pressure on his legs when he wakes up in the morning, but progressively gets a little better throughout the day. He has been complaining of headaches, "tummy" aches, has been having night sweats and is consistently waking in the middle of the night. He had a low grade fever for about 4 days, but then that went away. When we did bloodwork, they said his iron was a little low, and an "unspecified" tests was a little high, but nothing else seemed too far off. Would you see the blood counts changing first, or could it happen after you see other symptoms? And if it's not leukemia, what else could it be?