Hi,
Having read your info, I see you've just started SW after the Cambridge diet. I'm no expert on this, but do you think this might just be your body getting used to the dramatic change in eating habits? The nature of free food means you will feel full at times, but you shouldn't be eating until you are painfully so.
Please have faith in the SW plan - it really does work. I have struggled with my weight for a long time (sometimes more in my head than on my actual body!), but I have managed to lose weight consistently over the last few months by following the plan.
Good luck, and don't give up!