Below is a link to The Mayo Clinic which may help you: www.mayoclinic.com/health/lupus/DS00115/DS
I had 2 friends with Lupus - mother and daughter. They had to be particularly careful in the sun - wearing plenty of sun protection, and also eat a healthy diet - the link explains that, BUT that doesn't over-ride what your Dr suggests. You are best to have this discussion with him/her and ask for a referral to a Dietitian, particularly if there are other health issues involved.
It may be worth talking about how you feel, too! It isn't uncommon for a person to suffer from Depression when diagnosed with a chronic condition. It may be that a little Therapy will help you through it by giving you the tools to a healthier mind-set.