It does sound torturous.
Yes, you can cry in your sleep. When I was in that period of my life that I was just talking about, I went through exactly what you just described. I sobbed and cried in my sleep. Sometimes it was like I was in some hazy foggy dream. I wonder if it was because of what was happening to my brain from the trauma of the betrayal. I remember waking up to a soaking wet pillow. I remember waking up crying, from the depths of my soul.
I don't know what your swings are. All I know is what they were for me. The way the doctor explained it to me was when you suffer a loss or a trauma like I did, the neurotransmitters (chemicals like dopamine) in the brain go haywire. Think of it like a drop in the level of good chemicals in the brain. When those neurotransmitters go haywire, your emotions fluctuate like that. I am willing to bet you are very stressed right now but not aware of just how much.
Are you able to eat?
The questioning and accusations from him could be anything but just sounds typical to me. Sometimes the cheater accuses in order to draw attention away from themselves. Sometimes they do it to justify their own cheating. Sometimes they do it so they can blame you. Sometimes they fear that now that you know, you will do the same either to move on or to retaliate.