Well, back in 2018, I had a similar reaction (except the bleeding.) My doc wasn't too helpful, but his very experienced nurse was a gem. Here is what she had me do:
Star the medications, one at a time, at bedtime with a little food. Take for a week, if no severe reaction, start the next for a week, then the third. By taking with a bit of food at bedtime, I was asleep for the worst of the nausea. I also started a daily probiotic.

At the suggestion of other people, who had been through the antibiotics or chemo, I started eating tiny amounts of food every hour - maybe 1/2 an energy drink, 4-6 oz of a smoothy, 1 oz of cheese, 4 oz yogurt, a few cashews, 1/2 an apple... Also, I discovered many years ago that something about an apple or applesauce (but not apple juice) tends to settle the stomach.

Neither of these were a "magic bullet" - I still felt lousy, but was able to stay on the meds long enough to get rid of the cavities in my lungs. Now, almost 2 years later, I maintain with daily saline nebs and airway clearance.
Good luck, and let me know what your doc has you do.
Sue