Oh, Jayne, I'm sorry you're having a bad week! You're right about going slowly with the eating; keep trying different liquid things (have you tried making a smoothie in the blender?). Do you have meds for nausea? I had to take them often during treatment, and they really helped.
Don't worry too much about cleaning your obturator -- just stick it in a glass with some warm water mixed with mouthwash and then give it a quick brush with the toothbrush. No need to fret about it too much.
Take it easy, honey -- you'll get through this. I wish I had a quick fix for you, but you just have to hang in there. You're counting down now! Only 8 to go! Keep writing anytime you need to vent. We're here for you.