First things first. stop panicking. stress can cause problems with weight fluctuation. You appear not to have an awful lot of weight to lose. Were you dieting before SW last week? IF like me you already grill all meat, cut fat off meat, have skimmed milk - don't take sugar in tea/coffee and drink little or no alcohol THEN it will be even harder for you to lose weight.
You really need to talk to your C at class tonight, show your food diary and ask her to really look at it and see what is going on. BUT above all stop stressing and panicking...................relax a bit.
Are you due for a * week? do you have bowel problems - constipation etc - do you suffer from excess bloating? Are you drinking water and drinking loads just before weigh in etc.
Have you tried a red week? A green week, a plan that is different from the week before?
All these things need to be taken into consideration.
Once you start to lose, you will be losing, no problem.
GOOD LUCK FOR TONIGHT.