With your light always on at bed time, you are scared something chronic in life about something.
Normally only kids need the light on. So you are scared of some imaginary monster, unless it is a real experience, or a past one haunting you. You must know what, unless suppressed memory.

Always glancing at your bedroom door might be a worry, a sign.
When you turn on the light, in your mind because you are in darkness regarding this, something bad would always happen. So that sounds like what did happen or what you fear will, maybe again.
It sounds like you might be screaming really loud to wake yourself up from the nightmare in reality.

Sometimes you may be talking with your mom in your mind, for advice or help.
Can it be the loss of her causing this?
How long have you been dreaming like this? What is the real nightmare?