It's so bad that he's contemplating moving back up to the UFC welterweight division:

The New Mexico native on Sunday night left a somewhat cryptic message via his Facebook page stating "going back up to 170."

When contacted by MMAWeekly.com, Jeff Clark, Sanchez's manager, indicated that there has been no official decision made at this time about what weight class he will compete in next.

Its gotta suck to be Diego Sanchez.  He lost against the two top welterweight contenders while fighting there, although he was relatively competitive against Josh Koscheck and Jon Fitch.  However, he got absolutely destroyed against lightweight champion BJ Penn at UFC 107.  Yall know I'm not a fan of MMA math, but if we'll recall, BJ Penn got the same treatment against welterweight champion Georges St. Pierre at UFC 94.  So basically Diego Sanchez is now a gatekeeper in either division he decides to fight in as long as both of those guys are champions in their respective divisions. 

HT: MMAWeekly