I would be more terrified not taking the antibiotics. I formed a 10 cm cavity in my upper left lobe waiting to start treatment. I've been on the big 3 and only had a bit of "bathroom" issues but nothing that Imodium didn't help.
I also do the inhaled Arikayce, nebulize Levalbuterol and Saline twice a day with lung clearance.
Best of luck through treatment. It's do-able.