I frankly hate going to the doctor whenever I have a problem because they *never* seem to be able to find out what it is - it's so frustrating. So I totally see your point there. (I waited 6 months through pain before just seeing the doctor last week just because I thought it was either a certain supplement I was taking, or a pinched nerve that was causing a problem with my toe and hip/quad).
Ironically, the pain I felt through my hip to my knee caused me to collapse (somewhat) to the ground a few times. Anyways, fearing I was getting some type of arthritus, the Dr. said she thought my "hip" problem wasn't a hip problem, but that one of my muscles was way too tight. She thinks the toe is a pinched nerve.
What was the point of my story? Oh yeah - my self diagnoses was wrong. It wasn't any previous supplements (X-Factor) and it probably isn't arthritus. I'm glad I went, and I'm glad they FINALLY had an idea of what was wrong (I have a bad track record with dr's).
My initial thought for you was blood flow related. But then I remembered you had lupus, and if I can't diagnose my own problems 100%, I'm definitely not going to take a chance with someone over the internet. You're a very sweet girl, and I've read your posts before (I'm thinking that both the lupus and the recent Jeep purchase is not a coincidence to a different person who was on here), and I'd hate for anything bad/worse to happen to you. I'm not saying that there are people out there that deserve bad things to happen to them (although, sadly I do think that), but you are definitely not one of those people, and it makes me sad to hear good people like you having bad things happen.
So my advice is to go the the doctor - the stupid doctor who will poke and prod you and most likely not find anything. Sometimes time heals things in our body (cuts). Sometimes time destroys our body (cavities in teeth). Waiting until your next appointment might make things worse. Just because of your medical history, I think the stakes are a little higher with you when anything out of the ordinary happens. But honestly, if anyone else falls down a few times while walking, regardless of their health, I would recommend visiting the Dr.
Here's hoping it's something simple like a pinched nerve or too tight of a muscle.