Toddler started screaming at bed time - HELP

[Tonsley38]

My 21 month old has been a great sleeper to date, going down really easily and for 11-12 hours. All of a sudden last week she hasn't been going down at all and waking throughout the night screaming furiously! She won't let go of me when I go to put her down and then continues to scream and scream, violently! I have tried milk, holding her in the nursing chair, stories, leaving her and nothing works! Eventually last night I went in after one hour and brought her into my bed for the first time as I am desperate after one week of no sleep.
What is going on?!? Please say this isn't the start of new behaviour? Any tips?

Watching with interest as my 21 month old has started doing the same (although has never been a great sleeper).
She would go down ok after a book but is now standing at her door screaming and banging door.
Its been like this for about a week
Im exhausted

Have you tried a night light and leaving the bedroom door open?

There comes a time when children quite suddenly become scared of the dark.