Hi.I'm sorry you're going through this.
I would not leave her to cry as this doesn't really do much,apart from making the scream more high pitched (as you probably know)
The thing that worked for me was to go in the room when she was crying,lay her down,go out of the room and count to 10.Go in,lay her down,go out,count to 10,repeat this until she finally goes to sleep.
I will warn you.It takes a while,the first time I did it,it took about an hour,(which was actually quite good considering it was taking 3-4 hours)It took a good couple of weeks to get into,but the time it took got less and less,by the third night we were down to 25 mins.
I have see others on this site saying about having the chair by the cot and gradually edge towards the door over a few nights/weeks.There have been good feedback on that as well,I haven't tried it myself.
Let us know what you choose and how it goes. :wink: