Hi Laura. I started the Big 3 three times a week in February, had a rocky couple of months, but am feeling much better now and coughing so much less. I take 500 mg Azithromycin and 1500 mg Ethambutol with breakfast and 600 mg Rifampin on an empty stomach (although with a full glass of water) before bed, a dosing schedule I learned on this site. And every single day I eat a 5.3 ounce container of Greek yogurt, which has kept my digestive system comfortable.

Those first couple of months, while your body is adjusting, can be tough. I too experienced some nausea and loss of appetite from the Azithromycin and Ethambutol and often felt crummy the day after taking the Rifampin. My pulmonologist said it was okay to take ibuprofen for the fever and discomfort.
My heart goes out to those taking these drugs seven days a week; that must be so much more difficult.

I hope you are able to give your body time to adjust to these powerful drugs. They are effective precisely because they are so powerful! Do you have monthly sputum testing done? My April samples just came back negative for AFB, which makes me glad I persisted through those first months of discomfort and feeling sick. Wishing you strength!