Curious.
Does the sick feeling happen BEFORE you take the bite or sip?
If so, it could be anxiety. If not, it may be a part of your healing process.
First, call your surgical team or nutritionist. Rule out any organic causes. They won't mind if you call.
If everything is intact, you may be having a psychosomatic reaction, based on your eating disorder. OBESITY is a symptom of an eating disorder.
We can't give medical advice, and how you recover is important for your doctor to know.
Sometimes a course of omeprazole and/or ondansetron can get you through a stage of nausea. M of M or any OTC medicine really won't help you. Those two above are Rx strength zofran and proposed. Take the Rx by asking your doc. Once you're healed, you may never have nausea again.