I have an example why a doctor wouldn't want you to overthink a possible lupus diagnosis:
I have a neighbor who has "possible" lupus... she is changing her WHOLE life to accomodate this new "death sentence"... she is literally getting rid of everything--cars, house, everything. She's moving from her lifetime home (thinking it will make her better to move), and exhausting herself with stress.
I am not even convinced she has lupus. She has no "typical" symptoms outside of fatigue. (She just got over a longterm unrelated illness, so that's normal.) Her doctor made the "diagnosis" with no bloodwork, and only one office visit.
I love this person and her family with all of my heart, and it is so sad to me to see her throw everything away... I know that if it is indeed lupus, none of these changes will mean anything anyway... so she'll look back in retrospect and regret it.
So, I can see why a doctor would ask you to avoid overthinking this possibility...
research is a good thing
Don't let anyone ever tell you to not learn all that you can about any subject that is important to you, especially one that is this important. I'm a teacher, and so I was trained in college to do research. I ALWAYS research everything very carefully. When I was pregnant with my first child, I very carefully researched pregnancy, childbirth and breastfeeding. A few years and a few babies later I was a midwife's assistant and a La Leche League Leader. I LOVED educating other Moms. Knowledge is power, and if you understand what is going on with your body, you won't be so fightened and vulnerable and will be able to play an active role in your health care. This was true in maternity care, and I'm sure it will hold true in care for Lupus.
I'm newly diagnosed also, but I've been reseaching everything that I can find out about it. Even a couple of my students who have dreams of being doctors have been researching Lupus since I mentioned it to them. Who knows? Perhaps those two will find a cure or a great treatment for Lupus out of love for their old Latin teacher!
Keep learning and don't feel guilty about it.