I don't understand the extreme highs and lows

I close my eyes and i see myself on a busy street with many faces of people i don't know , looking at me and passing by. It keeps fast forwarding and i am not sure if i am walking through the crowd or i am just frozen there.

The more the visual fast forwards i feel sick and dizzy in my mind. I even threw up today because of these meaningless things in my mind.

I worked more than 15 hours a day in last week with little or no sleep but that was only to get distracted from what keeps going on in the mind.

As i closed my eyes a moment ago i visualised that I'm in a dark room feeling suffocated and I'm banging the door hoping someone would let me out.

There has to be a reason why my subconscious is messing with me but i can't put a finger to it.

All i want desperately is to sleep peacefully for a few hours.