What should I do???

So I've been on Duromine 30mg for a month, I lost 4 kgs the first week and that's all...I didn't have time to weigh myself the 2nd/3rd weeks and I finally weighed this morning hoping that I lost at least 2 kgs so I'm finally below 100 again but i was hit with huge disappointment when I saw the same number...i feel so blue right now cause I haven't eaten much for the whole time I was on Duromine and I have been walking much more than usual!! I don't know...should I buy the 40mg one?? Or should I just stop using it??? I feel like giving up when i have literally just started dieting in November smh