Coincidently I have recently decided to have a bit of a push in the gym myself. For the last 2 weeks I have been abstaining from b00ze, eating healthily and working out 5 days a week, I have been walking home when I can, I estimate I have walked 14 miles in the last 14 days. So how much weight have I lost? None, in fact I am 1lb heavier! the only reason I have not jumped off a cliff is that I have dropped a trouser size, so obviously I have lost fat but added heavier muscle. You are no different, Forget the thyroid cobblers, that's the usual excuse, very rare and even if you have a problem that doesn't change the laws of physics! Good luck, keep doing what you are doing, there is only one way, eat less move more!