Aligner Irritation Inside of Mouth

Anytime you have something new in your mouth, especially, there is an accommodation period where there may be soreness or even some irritation to the surrounding tissues.  Having worn aligners myself and having treated hundreds of cases myself, I can tell you that both of these issues diminish or go away after several weeks.  The aligners are overall much more comfortable than braces, so hang in there with Invisalign and I am sure you will be over this phase very soon.

Actually the irritation will not go away unless the source of the irritation is taken away. That may mean that there is a part of the aligner that is rubbing the inside of your cheeks. Your doctor can trim the aligners an/ or polish them.
It seems your math is accurate. However, in many cases there are additional aligners needed to achieve the final goal.
Speak to your doc about the timing as well. The aligners should be worn about 22 hours a day; if you do the math there is a possibility to speed the process. I don’t recommend it, but I have seen patients like you, and I get it!
Have fun. Hope this helps!