That mustang driver was way out of line and is lucky he wasn't observed by law enforcement bullying a cyclist and driving erratically. The poor fellow must have some serious personal problems.
Use the opportunity to think about anything you can alter - your route, departure time, riding approach. If everything is as you want it to be, proceed. Sometimes you will encounter a jerk on the road (more often in some places than others). I have found that there are very few positive outcomes possible from letting it get to you emotionally. Stay cool and keep your wits about you so you can watch for other traffic and complete your commute. After the ride, do your thinking/analyzing.
In my town, over 99% of the drivers I encounter are regular folks just trying to get from A to B. Occasionally a Neanderthal will cross my path, and I try not to let it bother me as best I can. Good luck, I hope things settle in better for you on your new commute.