Hi and welcome to the community!
I know dealing with mystery symptoms and not having a diagnosis can be hard, but I am glad you are pursuing answers. You deserve to have your concerns addressed and getting treatment can improve your quality of life, so don't worry about being seen as a hypochondriac.
While your symptoms sound like Lupus symptoms, I can't offer your a diagnosis or input, for your safety. There are other autoimmune conditions that share symptoms with Lupus (like RA, Psoriatic Arthritis, and the like), but the weight loss element is definitely more of a Lupus symptom. Some of our community members deal with pretty consistent joint pain, while others experience long stretches with little to no joint pain. I don't know if you've already checked out our symptom information on the site, but here's a link, just in case -- https://lupus.net/symptoms. I would definitely plan on going in with a list of your symptoms (and how long you have been experiencing them) to discuss with your doctor. And you can ask for specific tests to rule out Lupus and other autoimmune conditions. A specific panel of bloodwork is a good place to start -- https://lupus.net/blood-tests. You can also ask your doctor for a referral to a rheumatologist, especially if your bloodwork shows a possible diagnosis of Lupus.
I know dealing with doctors can be intimidating, but you are the own expert on your body and if you know something is off, well, then something is most likely off.
I do hope you get some helpful feedback from other community members and can maybe offer more tips and suggestions.
I hope the appointment is fruitful and that you get some answers as to what's going on! Keep us posted, if you feel comfortable doing so.
Best, Erin, Team Member.