I looked for conditions likely to cause constricted pupils, removed any that were unlikely based on your other symptoms, and came up with this list. The first thing I thought about
was a vasovagal episode, and it may be, you were lying down, got up, and blood pressure could have dropped. A vasovagal response would produce most of the symptoms you described. The constricted pupils were listed by some sites as being vasovagal, others listed dilated pupils.
Generalized anxiety disorder
Generalized anxiety disorder is a condition in which a person has nearly constant anxiety.
Fainting (vasovagal syncope)
Before fainting, you might feel lightheaded, warm, nausea, a cold sweat, or have tunnel vision. (You can have a vasovagal reaction without fainting).
When someone has a panic attack, that person feels a sudden, intense fear that can't be controlled.
Hyperventilation is rapid or shallow breathing usually caused by stress or anxiety.
The Autonomic Nervous System, which the Vagus Nerve is part of, can have fluctuations in it's performance as well, and if you're afflicted with anxiety, even more so. The autonomic nervous system consists of a sympathetic and parasympathetic side.
The sympathetic prepares you for fight or flight, faster heart rate, suppresses digestion, dilates the pupils, raises the hairs on your skin (I'm sure you've seen an angry dog, the hairs on their back stand, they bristle, that's fight or flight).
The parasympathetic system calms everything down, constricts the pupils, relaxes the hairs on your skin.
Here's an idea of the complexity of these systems. www.merckmanuals.com/professional/neurologic_disorders/autonomic_nervous_system/overview_of_the_autonomic_nervous_system.html
Be sure to discuss health concerns with your doctor. You can keep a diary of incidents, day, date, time, what you were doing (sitting, just got up, walking, etc), and a brief descript
ion of your symptoms. It may help you, or your doctor, understand if there's anything in common.