Liliann, do yourself a favor and treat yourself to a new scale. The one you're using at home is clearly broken.
Remember that you posted about your broken scale yesterday? Does WW takes insurance?
It's a good idea to weigh yourself or get weighed regularly to monitor to your progress and tweak your eating and exercise if necessary. Three months is a pretty long time to go without checking. Would you consider monthly or every two weeks? Do you see your doctor fairly often? You could use his scale as your official scale if you do.