In my opinion, don't weigh yourself, it will do your head in. Take a full body image (photo) and then in 2 weeks time take another one. You will see slight changes, don't depend on the drug to do all the work for you. By what you are saying, you are exercising, you are going to the gym, remember muscle weighs alot more than fat, so even though you are losing fat you are gaining muscle which means by weighing yourself the scales are now weighing in with more muscle.
The good old way of telling changes is through your clothes, this is what will give you the real deal tell tale sign. Eat 4-6 small meals a day, if you don't feel hungry, please try and eat because the body metabolises better if it is given food on a consistent basis. Healthy food of course
Also remember at the gym you will need to change your routine around both weights and cardio, the body has an amazing ability to get used to what we do so we need to always suprise it with domething different (it called muscle memory, it knows what to do and just does it without trying) so shock your body every two weeks.
I may just mean to up the intensity of your cardio or even try lighter weights with higher reps or heavier weights with fewer reps. Oh, but the most important thing is, you want to do this, if there is no motivation you're lost the battle, it needs to be a lifestyle not a quikfix. If you have that attitude (and I'm not saying you do, because your here) you will go back to the habits and weight that made you come here in the first place. Rock on say fab, and healthy living. Oh, it is also okay to have a cheat day, what this does it shocks the body and makes it work to process the food which also can be of great benefit.