Finally cracked...

After a long slow climb I turned onto a new hill that I found on Strava and cracked.  Looking down and seeing my CatEye show a gradient fluctuating between 10%, 13% and 17% yielded the probable reason.  Even my bailout gear wasn't helping me.  It make me wish I had a triple and could just tirelessly spin my way up.  Net result:  have to try it again and maybe burn a little less energy on that long slow climb...must...get...to...the...top...