@itwasnevermine as others have said, lots of posdible reasons why you've not seen a loss - lack of water, inflammation, your body recognising it is ill and holding on to energy sources.. Plus if you look at long term weight loss graphs on any weight loss approach there are daily and weekly fluctuations up and down. It is only in the longer term that you can see the overall downward trend.
Plus, one of the things I like about this medicated approach is how difficult it is to 'just give up'. Firstly you can't undo whatever weekly injection you've already taken so you're committed until those effects run out.
Secondly, unless you're on your final dose from a pen you've paid a small fortune, so you might as well get your money's worth and finish what you have.
And thirdly (ime) on this medicated approach you can't easily say fuck it and stuff your face (like you might on any other diet). You could order a huge Chinese but find you couldn't eat as much, or try to stuff your face with chocolate or wine only to discover that you had to stop. Or risk being sick with all of it.
Originally I hated the idea of a once weekly injection, now I think it is part of what helps us stick to this through the ups and downs.