the starting dose of Pristiq (50 mg) is FAR higher than the starting dose of Venlafaxine that we recommend (12.5).
You can ask your doc for just venlaflaxine ER and start at 1/3 of the capsule. Which is what i did for VM. MDDS is a migraine variant too. I have same sensation as you lying down as everyone who has VM. My initial episode was set off by prolonged stress as well.