It is about internalising a good object (person). One notion is that when mothers mirror (validate / soothe) their infants that leads to secure attachment where the infant feels safe and happy in the mothers presence... Then later the infant internalises the object and can comfort themself in her absence by thinking about the mother and the infant has always experienced her coming back too...

Therapy is a little like that all over again. It can be hard to self soothe when one doesn't have an internalised good object... People can experience seperation anxiety where they are afraid that the good object will disappear when out of sight or never come back.

On the upside... I think it is meant to take some time, but it will get better. Do you know her well enough to have imaginary conversations with her in your head? I know I went through a phase of doing that... When I was having a hard time I would imagine what I thought she would say... Also transitional objects like a tape of her reading relaxation stuff or something like that can help too...

Hang in there.