Frankly, I am not sure what you gain by switching to a new instructor. Could be better, could be worse. A long season tends to tire the player out and bad things can creep in. IMO, go back and start from ground zero. Go over all the fundamentals. Do a lot of tee work and front toss. Focus on barrel control. Sounds like you'll need to find a facility to rent a tunnel during the winter. You should see some improvement and confidence in a few weeks. If not, then consider making a switch. Good luck.