K., it isn't "giving in to her" to go to her when she cries. She is not manipulating you and crying because she "knows you will come to her when she's in child watch." At eight months old, she is not capable of that kind of thinking ahead and manipulating an adult; she does not understand yet you will come back, because at her age, when you disappear you disappear forever and entirely, in her mind. That's what separation anxiety is all about and all infants go through it. She didn't love child care at the gym previously; she just hadn't entered the perfectly normal stage of separation anxiety. This is not a matter of disciplining her or forcing her to endure while you're away. Change your workout routine, work out at home, or temporarily find a 24-hour gym where your husband can be home with her while you work out at hours he can do that. When she's a toddler and staying in gym care, day care or at preschool, you will deal with it differently, with verbal reassurances and returning to check on her and ensuring her caregivers are playing with her well and distracting her, etc., but right now she is a very small infant, and the only way to reaassure her is to be there with her.