I've also had really bad nausea and have tried a plethora of drugs. During AC we found admitting me to hospital for the night after treatment for fluids helped a lot along with getting on top of heart burn. I also made myself eat as I found if I let myself get hungry I'd feel even more sick.
Once that was generally under control I just had to deal with the other side effects like my mouth and throat. Dry mouth and throat, ulcers and oral thrush. The worst. I stopped with the salt water as found it was making me more dry, and the dryness seemed to trigger the ulcers and thrush (for me). Nilstat for oral thrush and Biotene mouthwash for the dryness. Using it a lot during the day and night.
Also, drinking a heap of water helps both nausea and the mouth issues. Even when feeling sick and the throat was really sore, I'd make myself drink.
Really hope you've been able to find a good balance to manage your side effects since your first round. Good luck with it all!