Sounds to me like this is a fairly normal reaction in terms of what I've read and experienced.
With my own first dose of RT I also had 6 weeks of chemo. I felt that the excess mucous in my badly ulcerated mouth and burnt throat were the worst of the side effects. I would say that these peaked about 4 weeks after treatment had finished. It certainly wasn't easy but I did get through it.
My speech was affected and my skin did break down (like bad sunburn). However, about 2 months after treatment had finished I slowly began to eat solid food again.After 3 months, my eating was almost normal and my speech much improved. I know that this sounds like a long time, but I just took it one day at a time as the cliche goes.
So. . I hope it all goes well. It is tough. . very tough, but doable and a new normality is certainly possible.