Stuck in a scary situation...help?

Last night I was definitely having a lucid dream, but I don't know why it went so wrong. In my dream I was aware that I was dreaming throughout it, but at one point I did something extremely embarrassing without realizing it. It was weird because I didn't have any control over my one action, so I was kinda freaked out. The people standing around me (about 20 of my classmates) ended up trying to convince me that we were in real life because I wouldn't believe them, as I knew it was a dream. (also because what I did was so embarrassing I was really hoping it was a dream) Finally, they started showing me some paper with facts on how to prove I was really in real life, not in a dream, and they started reading it out loud. As they were reading it out loud I felt myself being "taken over" (?) starting in my stomach and chest, as if I was in the process of being slowly possessed. It was so fucking scary because I would try to fight the feeling but it kept coming back, all the while the voices continuing to chant in unison. By this point I was so freaked out I started screaming as loud as I could, hoping someone in the house would hear me and wake me up from the weird nightmare, but no one came. Apparently just because I'm screaming in the dream, hoping I'm screaming in real life too doesn't mean I am.

How can I prevent this from happening? Is there a way to change my dream when something goes wrong, or at least a way to wake myself up when I want to??

I remember watching a youtube video where reecejones87 explains his thoughts about 'layers' of a lucid dream. I remember he mentioned something about this in one of the lower layers so I recommend watching those videos (There's 5 of them and each explains his interpretation of each layer)

I have been afraid at times too. I have heard a technique of standing up to the scary thing. I have heard this makes it go away. Remember, nothing can hurt you in a dream...you are always safe. I will try the courage, turn about and face up to a scary thing the next time this happens. Ask it what it wants. Usually, I just fly away but this leaves me with a residual not so good feeling...like it may still be lurking about. I pretty much do this in real life too. Hmmmm. What is this type of dream telling me? Darn these mirror of dreams...I always have to look at myself and improve some character flaw!