uh-oh it's so cold!

My mercedes didn't want to start up this morning
I had B99 in it still on Sunday night b/c I didn't know it was going to get
so cold
Monday morning it started up with a little difficulty, and then I went
straight to the gas station and put a little bit of petro-diesel in it (so
it's probably about 70-80% biodiesel now)
It ran fine yesterday but then didn't want to start up this morning

I'm going to try it tomorrow when it's a little warmer out and hope it
works, but if not I was wondering if someone had one of those electric tank
heaters I could borrow, or maybe a fuel filter band too?

is my fuel filter probably clogged?
anyone have any other suggestions?

thanks