sleep screaming


My LO turned 5 months on monday, for about the last 2 weeks she has started screaming before she will go to sleep. She has never had a problem going to sleep before especially when I'm holding her. Now no matter what I do, if I'm holding her or she is laying down she screams her head off for about 5 minutes, sometimes she screams so much she makes herself cough. Anyone else experience this??? I am so lost don't know what to do anymore