Petra,
my Sister has Lupus, it is serious but it is treatable, she manages fine with the meds, in fact she's taking some of the same meds I'm on but only at a much lower dosage.
She also suffered from severe anxiety prior to her diagnosis, if it wasn't for a Doc at her practise covering for her own GP on holiday her Lupus might not have been spotted, her own GP was missing signs because they were focusing in on her Anxiety probs.
A bit like my own situation, I had been on Anti-depressants for years, along with many pain meds before I saw a fresh Doctor who immediately said to me... "Lets fix your body before we try to fix your Mind.", he realised (as I already knew and had expressed many times to other Doctors) that my depression/Anxiety was due to me suffering chronic pain throughout my body and that by treating my pain with new pain meds (that actually help ease my pain) then my Mind would relax and my depression/anxiety would ease, even cease.
And to be honest it worked, since I've been on the new pain meds I haven't taken any anti-depressants at all, been over a year now (except the wee spell when my Mum died last year) and I feel a lot better - ok, there was the other spell just before I returned a few months ago to NMP (I took a break from the World for a long time) but as I said I feel better with the Depression/Anxiety now and I'm managing it better.
If the NHS had more in the way to deal with all Anxiety & Depression types (more staff dedicated to the subject & much better training of the Doctors), other than just dumping pills on them & occasional CBT, then maybe they mighta noticed it was the pain causing mine and not the horrors I saw & faced throughout my life since I was 13, ok part of that was the cause & still is in some way (I still suffer nightmares about the horrendous things) but if the NHS had more then maybe I would've been sorted sooner and wouldn't have spent most of the last two decades suffering ever increasing pain with nothing but some pathetic pain pills & anti-depressants.
Even having a proper diagnosis is enough to ease Anxiety, it was in my Sister's case, even though she found she had a potentially life threatening condition, her words.
Lupus, is serious (if left untreated/unmanaged) as I said but it is treatable, or should I say manageable as it will be with you for the rest of your life and the meds make your life better but they are not a cure as such, don't panic though, like I said it is manageable and there is no reason why you can't live a long life. My Sister was diagnosed a long time ago and she's still going with no signs of stopping (just wish she wouldn't call me with such a lively voice though, kinda depressing. ).
Take care & be safe Petra.