As frustrating as it is, a 5 day stall is quite normal.

There is also a great article linked in the don't let the scale get the better of you thread that deals with water weight. I'm discovering this myself as I had been used to a pretty steady decline and then after adjusting my calories for activity, I sat for 2 weeks before the scale finally dropped. Apparently, as you lose weight, its a good chance you'll enter a "whoosh" cycle because the lighter you are, the more water weight and other temporary weight gain reasons can more easily mask the true fat loss, so you look like you are holding steady when in fact you are truly losing fat; you just have to lose enough fat that it over takes the water weight gains to show up on the scale.

The suggestion made in that article is give yourself a minimum of 4 weeks and compare your weight lost over that whole period of time. Make adjustments based upon that 4 week period. So keep things exactly the same over 4 weeks and then compare. Say you were 286 on April 10th, and you weigt in at 278 tomorrow on May 8th. 286-278=8 lbs. Divide 8 lbs/4 weeks and that equals a 2 lbs/wk loss rate which for someone with 100 lbs to lose, is still reasonable for a rate. The scale during that 4 week period may not go down linearly as water weight may be skewing the results during weeks 2 and 3. You can even stretch it out a bit longer.

If you see that in 4 weeks of the same deficit and the same exercise intake and same setting (sedentary, lightly active, etc) that the scale hasn't moved, then evaluate what needs done. Have you been adjusting your deficit as you lose weight? It's recommended to revisit the setup guide every 10 lbs or so because as you get smaller, your BMR drops because it takes less calories to keep your base needs functioning. Have you slipped up and gotten sloppy on your logging? Are you using a food scale to weight or just general measurements or guesses? Are you using accurate entries from the database?

Have you eaten out a lot recently? Sodium in restaurant food is notorious for causing temporary water weight gains. Have you increased your activity or done something in recent days that worked your muscles pretty good? New activity or activity that is strenuous can cause your body to retain water as it repairs itself. Have you upped your carb intake lately? The body retains water to deal with carbs, so if you suddenly increase the number of carbs you are eating, your body is going to take on more water. Have you started a new medication? This can cause water retention as well. Have you been under a great deal of stress recently? Hormone levels getting out of whack can cause water weight gain as well.

5 days really is not enough time for a true trend to be seen; many folks here have had water weight gains stick around for as much as 2 or 3 weeks - I have! My suggestion is to give it some more time. Look at what you are doing, tighten up if you've gotten sloppy on your calorie recording, double check that the deficit is still correct for your current weight, then give it time before changing anything.