One of many personal things I cant explain

i had something similar as a child. It was two quick vivid creams that happedned within a couple of minutes. these were dreans where you fall asleep so quick that the body hasnt; rested yet. The first dream i dreamt i was on a bike and i was floating in the air as i was doing this I awoke and as i awoke i felt as if i fell into bed as if i was floating and then fell into my bed, maybe my body jumped enough when i awoke that it felt like this, but it was interesting.
Then I fell back asleep a minute later and dreamed that i was doing something and in my dream i hit my head, then as i awake in real life i jumped awake and then hit my head on the headboard. How did my dream know that i was going to hit my head, i don't know?!!