14 month old always sick . in daycare for 5 months. she gets better a 2 days later she's sick again. on and off for 3 months. is it immune deficiency?

Doubtful: Children in day care facilities are being exposed to each and every virus that their playmates are carrying and this actually provides them with progressive stimulation and activation of immune processes. If you really feel that there is something seriously wrong your pediatrician can easily evaluate for specific immune defects, but really doubt that these are present. Best wishes.