Hi there!
Like you, I was also recently diagnosed with Lupus; back in June. I'm also 21 years old and about to head off to college, tomorrow. For the first few weeks, after being hospitalized for a month, it's a bit rough at first. Your energy won't be the same and you get exhausted more often. For me, I was very down for awhile. I got depressed, I cried but eventually I told myself that being mopey about it won't solve anything, so everyday, I did some sort of yoga or stretching to get my body moving.
It's basically baby-steps in trying to figure out what your limits are and what you can and cannot handle. My mom would take me out to go food shopping, and around an hour I would have to tell her I dont feel good and it's time to go home. But I always tried and get as much walking/exercise in as much as possible and now I'm able to go out for a whole day.
A lot of my family told me I should take off a semester and take time to recover. At first I was really thinking about it, since I was so sick and tired all the time. But as the days and weeks came and went, I was able to build my stamina up again and I'm able to go to school. The biggest thing is, if you tell yourself you cant do it, then it starts to get to you. Don't let the disease get to you, take control of it and don't let it hold you back.
Before the whole lupus, I played softball, I was involved with martial arts and teaching it at school.. So I was a very active person. But now with the lupus; i'm not really sure how that's going to work, but as long as you know what your body limit is, you should be okay. Just remember to take your time and don't rush into anything.
For school wise, if you do plan to go back to school; You should sign up for disability. So if you get sick or need to miss class for a doctors appointment etc... Your professors won't hold it against you (hopefully), and they'll know how to accommodate with your needs.
For the flare, i'm not entirely sure... Since it's been at least 2 months since I last experienced anything. From what I heard from other members, maybe about a week?
I hope that helps! And good luck with everything!
-Julie