Going through the weather records for your area on
Weather Underground , it looks like it has been 10 to 15 degrees warmer than average, and the trees have responded accordingly. If it's 80 degrees in mid-March, the trees are going to start blooming, they don't learn to keep track of time. The silver-lining on having your fruit buds die is that it causes the tree to put more energy into growing (instead of fruiting) so the next year's crop might be better.
I'm also in zone 5b, and the following video is one I took at the end of March 2012 showing apricots the size of marbles on the trees. While average highs for March are in the 50s, that year we had 17 days where it got up to 70 or higher. Eventually a frost killed most of the fruit. This year, we have only had one day where it topped 60 and everything is quite dormant so I am hopeful for a good crop this year.