Brekelefuw

I agree with Tony.
It may seem frustrating at first, but everyone is going through the changes that you are going through. You will get used to the hectic schedule and your practicing will become more efficient so you can take things in and apply them much quicker than now.
Not being prepared for a lesson isn't the end of the world. Teachers do understand how busy it gets, and they too have been unprepared for things. Talk with your teacher and tell him/her what you are feeling. The teacher will have great advice. All of mine were willing to lend and ear to my many woes about playing and being a musician.