If you have dropped the crap and stuck to a clean diet for 12 weeks mate aswell as cardio you should see some differance.

Do not loose heart though.... Help is all around!

I would get yout thyroid checked though, just to make sure its not that, 99.9% it wont be but just be safe and tell your GP you want a test, be firm and say you want one done as they will most prob' say no to getting it done.

Also are you on any other meds? The worst are Anti-d's. Now I know some folk have to take these if it be for anxiety or feeling crap and I know many of them work but the majority put weight on or make it very very hard to loose weight whilst on them.