Well, I can tell you that it is not important to lose weight every week. It isn't even important if you gain every once in a while. It is only important that you are losing more often then you are maintaining or gaining. If you lose 1 pound for 3 weeks, and gain 1 the fourth for every week in the next year, you will have lost about 39 pounds by this time next year. Do that for 2 years or 2 pounds, and you have 78!
One thing I can suggest is something that I do when I know that I am going to faced with some "extra" calories: I make sure to get some "extra" exercise. Not only does it take the edge off of the indulgence, but I just feel so much better about myself.
So don't let this little bump bother you any, you're doing great! 17 pounds in a month is wonderful. In fact, you could only lose 3 pounds this month, and still be averaging 10 pounds a month.