I'm a migraine sufferer and have found great relief from nortriptyline. I recently heard a loud swooshing in my ear for a couple of days. Problem?

No. The carotid artery normally passes though the bone that houses the auditory nerve. When air conduction is temporarily impaired, one hears the internal sound which is soft and usually not audible. A "clogged ear" like after swimming, from a wax impaction, following a cold, or changing altitude can cause this. It's not serious. Lying ear firmly down in bed can temporarily reproduce it.
Swooshing in Ear. The loud "swooshing" sound in your ear is very likely your heartbeat. Try taking your pulse to see if the the sound corresponds to your heartbeat. Another possibility is spasm of one of the two muscles in your middle ear, muscles that dampen the eardrum from loud noises. This is called tensor tympani or stapedius myoclonus. This sound will be must faster than heartbeat. See an ent.