Ok, well Lupus at 48 is rather uncommon. Even if you did have Lupus, why would you end your life? Would you really want to succumb to this? You have to be stronger than that! My grandfathers brother had Lupus, guess what age he lived to? 92, no I am not kidding you NINETY-TWO. My grandfather who was perfectly healthy lived until 88. Lupus is known to often go into long periods of remission in which some people can even reach nearly a decade of symptom resolution. Would you rather not have it? Of course, everyone on this forum would like to be able to eat gluten without it destroying their intestines but you learn to cope and you become stronger because of it.
You sound like you are in awful shape right now, so it can only get better from here. If you get diagnosed with lupus, well guess what? You get treatment, and it will help push it into remission. At this point, it is only upwards for symptoms so don't give up and don't even think about ending your life because of it! There are a lot of people here that have multiple autoimmune diseases, they are all doing fine.
Go look through my old threads about my panic about Celiac when I was first faced with it's probable reality, I look back on those posts and laugh now. I also had a childhood friend that was diagnosed with Lupus very early and he is as healthy as anyone else, in fact at this point I would say he is in much better shape than me and most of my friends. The anxiety and depression that come with being newly diagnosed are temporary, you are in a TEMPORARY state of mind right now so it is very important to not act out in any harsh way because of it.