If I give notice and it is accepted, can I be let go before the agreed date?

I gave a longer than normal notice for a job I am leaving. My boss knew it was coming and asked me to give more time because the holidays were coming and there were concerns we would not get it all done. I told him I was nervous about doing that as I did not want to get let go early. He said "Don't worry. That doesn't happen here." So, I gave ~5 weeks notice. I am just about finished with the transition work and there are still just over two weeks to go. They told me today that Friday would be my last day. My boss says he fought against it, but he was ordered to do it. Do I have any recourse? Letting me go early costs me 2 weeks of salary and a month of health insurance as my last day was in January.