There have been two pieces of news this week that are very negative for housing and by extension the economy. The first is that the FHA wants to tighten its lending standards. The marginal loan these days is made by the FHA, not by subprime lenders. This move would crowd out the marginal buyer.
The other negative is the move higher in rates today. If the economy were really getting better that might offset part of the rate effect, but I believe all that changed today is perception.