Based on your description of the accident (if I understand correctly), you might want to ride more slowly and cautiously in that situation. Splitting lanes is inherently dangerous. I can't imagine splitting lanes at a speed that would put my head through a window. I'm probably going 10 mph or less in that situation and a car cutting me off would cause me to rack my nuts on the stem or something.
It doesn't sound like a helmet would have helped much in this particular case, but there are plenty of ways this accident could have played out where a helmet would make all the difference.
Edit: Glad to hear you're alright.