Low IgG, High lymphocytes & low grade fever for 4 months

Hi,
My 15-month-old daughter is miserable. She's had a low-grade fever (anywhere from 99.5-100.5) every single day since Feb 15th, going on 4 months now. She's had 3 CBCs done in the last month and they show consistently high and consistently increasing absolute lymphocytes (now 11.3K), consistently increasing WBC (now high at 14.5K) and with the last test she now has low absolute monocytes as well (0.1K). She also has low IgG (510) which was only tested one time. We've been referred to an Immunologist, but it has taken forever to get in with him. She's getting more lethargic and now she's hitting her head and crying like she's in pain. She feels better when she hangs upside down off my lap. She'll lay like that for 30-45 minutes. What could be wrong with her? Her lymph nodes, liver & spleen aren't swollen. Anyone? Please help, I am so scared for her.

Thanks,
Lerie