It's hard for me, too, in therapy as I was ridiculed or dismissed for showing emotion on my face when I was a kid. I grew up despising and fearing emotions, being embarrassed by them. Some of us have heard many times over, that phrase, "Wipe that look off your face, or you'll be sorry".
So, now it's difficult and embarrassing with T even tho I know that's what she works with all day with others. I'm especially embarrassed when something slips out without my knowing it in advance or allowing for it. I know it's a result of the mistreatment in the past and more time with your therapist will get you used to emoting with her.
I know of many people who can't respond to other's emotions because they don't know their own, or don't approve of their own. I've worked different places where an employee might faint, have seizures, or get hurt some way, and everybody stands around, and some giggle from being uncomfortable. They're not actually laughing at the person's hurt, they are just so nervous about it all.