I'm coming in a little late on this subject. I have been diagnosed with Lupus CNS and experienced memory loss. However, my loss also included getting lost in familiar places, not knowing who my children were, speech and motor problems as well as the short-term memory loss you described. I had been diagnosed with Dementia, and later Alzheimer's - I have been getting much better and it is now 2 or 3 years since I was diagnosed, so I don't think Alzheimer's is the correct diagnosis. If your short-term memory has been a problem for a while, then it would be good to get a neuropsych test done and get a referral to a neurologist. This may help distinguish between the lupus fog and perhaps a more complicated neurological problem. With my CNS I have had a bevy of neurological problems aside from, and leading up to, the dementia. You may want to note any sensory problems, muscle usage difficulties, meningitis like symptoms, migraines, eye problems, blood clotting, etc. I never realized all these things added up to a CNS disease. The neurologist knew immediately it was Lupus CNS. Back when, they did an MRA to see if there were blood clots or vascular problems. MRI to see if there were structural problems. Both turned out negative. The neuropsych exam was the only evidence that I sustained some type of organic brain dysfunction. They also can do bloodwork to see if you have the bio-marker(s) for CNS Lupus. CNS Lupus is very rare and extremely hard to diagnosis from what I am told.
Hopefully your Rheumy can sort this all out for you. I am not sure what type of Lupus you predominately have. Sometimes this makes a difference. Memory loss is frustrating, but it sounds like you are handling it well. I have notes everywhere and sometimes loose those too, but I get by. Hopefully, it is the Lupus fog which will come and go. I wish the best for you - Kristin