Hello Khione.
You are not alone in your inability to cry. Even when I do get teary at home the tears rarely come out of my eyes. I seem to only be able to cry at my P'doc's and T's. Even then it isn't often but the last couple of times the crying was like a damn had burst.
Some-how the part of us that can feel has been shut down for awhile. If you don't think your therapist will take you seriously then it is time to get another therapist. You need to be able to be heard.
It has taken me years to get back some sense of sadness (instead of being numb all the time) with therapy. I know I haven't answered you question, but I just wanted to let you know you are not alone.