Is it normal i can't cry?

No matter how hard I try, I just can't cry. For the past year now, the smallest things set me off, and I feel on the verge of tears. My voice gets whiny and it physically hurts to speak, I start to tremble terribly, and whenever I perceive I'm under attack my vision slows and I can only focus on my "target" as if I were an animal.

I try to make myself cry, because I know it's all bubbling just under my surface, as it has been for the past few years. My therapist asks me if I was told at a young age that crying was wrong/weak, and I said no (it's true, I can't remember this happening). However, I do remember moments in school where I'd be bullied and cried in public and felt ashamed. I think this has something to do with it, but it's probably tangled in at least a dozen other traumatic events in my life.

Sometimes, I get real close, or I get a tear out, but I cant help telling myself to stop it, and when I don't I cant cry anymore anyway.

I am terrified of another public outburst, so I really need to get this over with now. I am so sick of not being able to emote correctly, and I am really tired of feeling on edge all the fucking time. The fact that I can't physically grieve makes me impulsive, jumpy, quick to anger, and paranoid.