It could be low blood pressure or something going on with your innerear(s) causing a vertigo sensation. My mother has sclerosis and has BPPV, and can no longer have the dentist lay her back too far or have her hair washed at a beauty parlor. There are several different issues just with the ears that can cause dizziness, some are even caused by autoimmune issues.

Frankie, please see your rheum, since you're flaring.

What you're describing with dizziness brought on by head position changes is classic for inner ear vertigo, and I also experience it at times. A possible trigger is allergies, as sinus fullness can transmit pressure to the inner ear, causing this. We're in allergy season, so something like Allegra may help relieve the symptoms, as it does for me. You may not notice any major allergy symptoms for this to occur. It could be lupus-related, too. Many people--including the healthy--develop inner ear sensitivity with age, so this vertigo tends to be more of a problem.

There's a simple exercise that helps relieve inner ear vertigo, and it involves sitting down and making the head movement that brings on the symptoms. Then wait for it to pass and repeat it 5-10 times, a few times daily. This causes the inner ear receptors to adapt, so the sensation decreases. It's like being around a bad or good smell for a while (such as pet smells) — you stop noticing it because your smell receptors adapt to it. I've seen it work for many patients.

I have learned my lesson having too many falls when I quickly move in any direction. Slow is the way to go :-)

I have to rise slowly in the morning and not make a sudden upward thrust from laying down all night. I allow myself about 30 seconds for my blood to get to my brain. Then all is good.