First of all you need to look at the bigger picture. Our weight does fluctuate during the week which is why a lot of people will recommend not to weigh in the middle of the week. You have still lost 8lbs and I have no doubt if you stick to this, you will lose more.
Also, I don't know whether you are male or female but whether this is your time of the month or coming up to it ?
Try posting a food diary - people here are very helpful and will tell you whether it looks good or whether there are things that could account for this.
Best of luck.