I think Gurley is lost to McVay and the Rams. He has gone beyond frustrated and just given up IMO. 6 carries on MNF? 12 carries in the SB? McVay, for whatever reason, can't find a way to use, much less feature Gurley and I think Gurley's sick of it.
I also don't know what the team felt about trading away Peters. He may have been a locker room favorite for all I know and his departure was pretty unceremonious.
McVay is in some dangerous territory right now. He no longer has the Midas touch and if guys aren't buying into what he's selling, you get results like MNF.
I don't blame Gurley in this particular case though. I wouldn't be surprised if he feels like he didn't play a part in the loss so why should he feel down about it?