First I want to say that it's awesome that you have lost the weight that you have, take pride in what you have achieved, forget about the past 5 weeks and focus on the past 6 months. That is the first hurdle for you to over come so you don't become disheartened now that you progress has slowed down.
I am in the same boat as you right now, i made some simple changes to my lifestyle and the weight fell off me and now for the past 6 weeks the weight loss has been slow with gains and losses.
From the shock of starting a diet your body and lifestyle went through an overwhelming change and now after 6 months your -50 lb body has adjusted to the changes you made back when you started.
Now it's time for new changes and I don't mean just reducing calories again because you have to be careful or you'll start to starve yourself and that will have a negative effect on your weight loss. The best suggestion is to research so healthy eating and maybe add some exercising to you weekly goals. Without knowing what you have done and been doing it's a little hard to suggest what the best step is now.