
One of the characteristics of the disease is the severe fluctuation of the hormone levels (hyperthyroidism / hypothyroidism), which causes fluctuation of
weight loss and
weight gain. This maybe why you are able to loss and gain
weight fast at times as you stated. As your disease progresses you will find that you will not be losing weight as rapid as now, and may struggle with maintaining weight due to the condition of hypothyroidism, unless your MD puts you on medication.