Either your boss is an idiot and can't appreciate that it is a good thing to have employees share their differing opinions, or he isn't an idiot and will respect you for being able to express such an opinion once he cools down.
Hope he isn't an idiot. If so, you are screwed. If it doesn't sting you this time, it will eventually. Idiot bosses are the worst.
Not too worried about the long term because the turnover for his position is pretty high. The only thing I really care about is getting my $$$, which is coming up in the near future.
If you want the money, here's what you do.....You go back to your boss on Monday, and you explain to your boss that you have felt bad about how your conversation went. While you disagreed, it didn't mean anything more than you thought your job was to be an honest "sounding board" for such conversations.....
...BUT, here is the MOST important part....
You MUST tell your boss that you "hope this doesn't impact your (my) employee evaluation." This will FORCE your boss to acknowledge that this is a possibility, AND will put your boss in a situation where they won't give a bad review unless they have a TON of bad crap on you. Your boss will be on edge....it would be far easier for your boss to give you the appropriate review than it would to "punish" you....unless your boss is a psycho, then you are mumped.