“Once I had a nightmare about that room. ‘Then was when I woke up screaming’”-nightmares are often used to convey fear, so fear is one.
“Even though I was dreaming I knew exactly where I was. ‘I wanted to run away, but something was pushing me towards the curtains, and I started screaming for John’”- since it is a dream, moreover a in which they are unable to control themselves, dread and panic must’ve ensued upon them (them being the person experiencing these emotions.)
Short answer: they must’ve felt dread, panic and fear
First time answering so hope this helps and good luck!