I have no idea why you're getting sick on a weekly basis. This is an issue for a doctor to address. It may be serious. The fact that it repeats weekly makes me wonder what you ate that day or the day before, and if there's a pattern based on a type of food.
It could also be some kind of negative message that's repeating in your brain, like suddenly a voice is telling you you're fat and you need to purge your body of the food you've eaten. These messages are powerful but they can be counteracted.
But first, take it to a doctor, and specifically, to any medical professional related to your actual surgery at whatever medical facility you chose. This is simply follow-up, although it's been a year. It's worrisome, though you weren't specific about "getting sick weekly" and what that means.
You don't make a direct link to the surgery, but you are asking for help here, so it seems you may think it's related. Take the first step and find out what you can rule out medically. Let your doctor be your guide.
Best of luck to you.