New thermometer woes

[verbhertz]

So I'm sitting here as my first partial mash (and full boil) gets to a boil. I set my floating thermometer in and realize that I'm 90% sure I was looking at 56C and not 156F for my entire mash. Doh! I only have an extra half pound of light DME. On hand. Going to toss that in and RDWHAHB, even though I know this beer (Urca Vanilla Porter from NB) is going to turn out way off the mark. Anyone else ever made a similar mistake?

 

[verbhertz]

OG should have been 1.61, I hit 1.53. Could be worse I guess.