You might ask your doctor if you can experiment with a lower dose (with the XR, that's fairly simple to do by opening the capsule and downing a portion of the amount in there that you want).
Everyone's different...I suspect though that a lot of your side effects will disappear or diminish over time (though it might be months). When I started on Adderall (first regular, then XR) I too had noticeable "dry mouth" but that was one of the first side effects to go away for me. I also had trouble falling asleep, especially at first. Now only occasionally is my ability to fall asleep easily affected. Low-grade headaches come and go--nothing that really bothers me. I've never experienced nausea from it. The "rebound" was much more prevalent when I took the IR Adderall, XR it's there but much, much diminished, especially over time. I take .3 mg Melatonin in evening before I go to bed...don't think it does much for me but figure it can't hurt!
I think that dry mouth is somewhat common, just be sure to drink lots of water. The "funny" feeling may be rebound, try to drink a caffienated beverage at just before the time that it is wearing off, that may help. The headache, and nausea I have read parents complain of as initial complaints that sometimes went away and sometimes did not, be patient and wait a week, speak to the doc and see if there is a way to alleviate them. In fact I get headaches when I need more water...dehydration can cause them.
As for the sleep issues, it may get better once you begin to take the med in the morning, and if not, go to the dollar general or the gnc store, and get some melatonin. It works really well to aid you in falling asleep.
I also like Adderall for the first several hours, but hat the effect at the very end. And sleeping is a problem for me also with AdderallI meant to say "hate" not "hat"