You've been on alli for a while and seem to be doing well. It almost sound like you're coming down with a little bug or, perhaps, ate some contaminated food somewhere along the way. Your stomach is a bit queasy so try and eat lightly for the next day or so, and see how things go.
More SF drinks, some soup etc. are things you're likely to tolerate well.
I hope this helps. Please let me know if you need anything else.
Pat Baird, MA, RD, registered dietitian