Cassie,
These dizzy spells sound like they need further investigation...only because you mention they sometimes go on for several hours. I thought that you just had quick low-blood-pressure "rushes" as you got out of bed, from which we recover quickly once standing for a minute or so. But since you say they last longer, why not make an appt for a good physical work-up?
Taking a lot of Advil AND Excedrin together is (and you know this!) not a great idea. You are virtually taking ibuprofen, aspirin, tylenol and caffeine all at the same time, every time you do it.
Plus you sound like you are taking the Excedrin prophylactically "in case" you get a headache. Those night-time headaches are a royal (blank), I know. Mine are caused by a mildly arthritic neck. Much better now that I have a better pillow.
As for your twitching eyelid after you sneeze, that's very common. It's just fatigued muscle fibers firing. Of no significance.
But, do see your doctor...dizziness can be caused by a billion things, most benign and totally correctible, so why suffer?
zuzu