How long has it been since your first treatment that you're still feeling sick? As I said before be prepared to be sick to your stomach and GI problems. Take the prescribed anti-nausea meds, metacoplomide (sp?), every 4-6 hours with food. I also take a prescribed med to combat acid-reflux, pantoprazole, which I take once a day before I eat breakfast; but you can take another if acid reflux continues.
Fatigue is an ongoing issue; I sleep in the afternoons the first week after treatment. It's hard to resist the bed but I find that if I do, get out in the garden or walk around the house, doing some laundry or walking the dog, I feel a little more energized.
Enhertu may or may not be for you. But your oncologist should be monitoring you closely. Keep him/her informed if you don't get the attention and relief you deserve. Don't give up!

@margitdill I’m in a similar diagnosis, also with limited treatment options and feeling unhappy about my quality of life on ENHERTU. I get my 1st CT tomorrow after 3 rounds on it. You’re not alone in your side effects and questions about what’s next if not ENHERTU.