Lupus. Flares, Dizziness, Sun

I have been diagnosed with 5 autoimmune disorders, with test and 2 medical specialist, for 14 years. I have SLE Lupus involving heart, lungs, and discord skin lupus, Celiac, Hypo-thyroidism, Gerd with hiatial hernia, RA and Osteoarthritis, I am not complaining just doing the day by day life of a chronic disorder person, taking care of me. I retired at 63 yrs old and now 10 years later I have had to learn a lot with the help of a great specialist I found 12 years ago. My best decision was live a zen life style, very peaceful, no drama. Anything that can help me keep from stressing, I embrace, even if I become a home body very happy alone at home.
My symptoms come and go...but the one I cannot seem to manage is nausea and dizziness. I have passed out in different places. I feel this may be from my pulmonary stenosis, my artery is narrow and crooked, so air is force into my heart. I also have photo-sensitivity and with discord lupus, I am allergic to the sun so outside is where I will usually pass out. But it is now happening inside my home. I can sit or stand leaning or touching a hard sturdy surface until it passes. Does this relate to anyone and what do you do when it happens?