Are these reactions to stress strange?

Sometimes if I'm extremely stressed out (which is often), I'll freeze in a certain position and just stare, and I'll stay in the position without looking around at all or moving unless someone gets my attention. I am completely conscious during these episodes, and I know that I'm doing it, I just find it hard to get out of it without some outside impetus causing me to react. I also sometimes shake my arms back and forth while I'm standing while keeping my hands completely limp... If I'm trying to fall asleep and I'm extremely stressed, I'll end up having hypnagogic hallucinations much more easily... My imagination can become very vivid; I can imagine a voice or a face and hear or see it. Even if I look around, everything will look warped and I can see strange face-like images all around, and if it's really bad I'll think there is actually someone there and it'll be hard for me to realize until I become alert again, and realize that it's not real... Then I can't sleep. I even feel euphoric as I'm falling asleep sometimes. There things happen fairly often, but are much more common and much worse when I feel extremely overwhelmed by something. Is this just a sort of defense mechanism against my own anxiety, or do I need to go see a psychiatrist?