Righto guys I need your help..

Alexa is almost 18 months old & is absolutley horrid at night time with sleeping & I am at my wits end....

She goes down to bed about 7.30 with a bottle & her dummy & cuddly (sometimes she has a grizzle & other times goes straight to sleep)... but about 2-3am she wakes up & screams & I mean a high pitch scream & wont stop (last night she screamed for a solid half hour)...

She sleeps in a gro bag so she isnt cold, also I have an oil heater in her room to keep the chill off...

she wont settle at all unless you sit beside her cot (not really an option when both DH & I work fulltime)... as soon as you leave the room she starts screaming again... even if she is asleep before you leave the room..

Any ideas I am soooo sleep deprived I am starting to lose the plot!!!!