Week 2

It is not unusual to have a big loss the first week and a much smaller (or even no loss) the following week.
The first week is a shock to your body. Some people say you lose a lot of water. The loss in this week is often big. The second week, your body has caught up a bit. It is prepared for what you are doing and you have lost all the water it is willing to give up, it will make you fight for those kilos. You also get a bit confident with the previous weeks loss. You may be less diligent with your food. Some things slip past and you may stagnate.
Don't worry, write down everything you are eating and doing with exercise. Have an honest look at it. If you go another week or two and have lost any more, then I would be visiting the GP for another check up. Your GP may increase your dose or give you some advice.
Your weight can fluctuate 1 or 2 kilos in a day. I know this because I used to weigh too often. Make sure you only weigh once or twice a week and at the same time of day. Personally, I do it first thing, after I pee, but before showering, eating or exercising. Semi naked, just knickers and a tee.
If you don't have a lot to lose you may find the losses smaller than someone who has a larger amount to lose.
Everyone is different and it takes time. The Duromine is not a quick fix. I have ranged from having small gains of 0.5 kg to having losses of 4.2 kg. BUT over 18 weeks have lost 24 kg. As long as you keep at it you should get results.