Do you mean 2025 for your op or a year ago? If only four weeks ago what you are feeling is totally normal and your body is recovering. Hopefully you will soon find a routine that works for you with regards to being able to take a bit more food and fluids but take your time with sipping and eating, baby steps for now and then it will get easier. Try to get your vitamins in, especially now as you are eating less.
For me after the op I couldn't stand the smell of certain foods, even the smell of coffee turned my stomach but now all is back to 'normal' and I thankfully am able to drink coffee again.
With regards to the weight loss, it is different for everyone, I put on a few kg in the hospital immediately after the op and then slowly started to lose but I didn't see it on the scale or physically for quite a while. It will happen when your body is ready.
You have got this, it is early days.