As a HS coach I can tell you that, unfortunately, there are far too many HS coaches with egos out there that do not want a kid in your situation to be successful. You see the problem is that your coaching and commitment as a runner is far superior to your new coaches ability.
When a situation like this arises in HS an ego-centric coach will not allow it to continue as he will be exposed as a fraud and parents and other athletes will wonder why the kid not running his workouts and buying into his BS is far outperforming the ones that are.
Whereas a competent coach would encourage you to do whatever you felt was best for you and give you positive reinforcement and encouragement. Wanting you to succeed in everything and there to help if you need and request it.
I've had a number of privately coached kids in my program- and it was never an issue. Coaches that put kids first don't have an issue with this. In the end, I end up earning the kids and parents trust and I end up coaching the kid and saving the parents tons of money-- unfortunately there are coaches like your new coach that like to call kids names and demand allegiance so they are not exposed as frauds.
It's their protection mechanism, they can't allow you to run if you don't run their workouts.
Here's my advice- sit down with your new coach, tell him what you are going to do and what your goals are. If he is positive and supportive of your plan and just gives you some small advice or recomendations, you have misjudged the coach and continue on with your plan under the new coach. If he is not supportive of your goals, you simply need to continue on with your coach and do not let that new negative influence into your life. Your team is not competitive anyway (and never will be with an ego-centric coach as described), so go run open college races and plan on running your FL meet or NXN regional meet as your culminating event.
Good luck and if your love running try to walk on somewhere or run D3.