Did I really gain that much weight in one week?

I’ve been really sick this past week, and I’ve only been able to eat soup essentially. I knew canned soup has a lot of sodium, so I figured I’d have a small water gain until I got back on track. I felt better today and chose to weigh in to see I’ve gained nearly three pounds. I’ve been maintaining 120 lbs for four months and have spiked to 122.9 lbs. is this a true gain?? Would you consider this a setback? The soups were very salty, but I didn’t think I ate enough of it to gain nearly three large in a little over a week.

Is this a true gain??