I Have Recently Started Taking Escitalopram, Approx 3 Months Ago

I have recently started taking Escitalopram, approx 3 months ago at 10mg/d with the plan to start to taper me off of theDoxepin 200mg/d that I have been taking for approx 30yrs. I was started on 10mg of Escitalopram and it was increased to 20mg about a month ago as I started the Doxepin taper which was 50mg/wk. I am now taking Doxepin 50mg and Escitalopram 20mg and over the past few days I have had a great seal of difficulty sleeping at night. Is this from the Doxepin or the Escitalopram and should I notify my MD?