Replying to Cold weather shooting and condensation

Hello Media and Arts! I just got my first real camera (Canon Rebel SL1). I have a few questions.

1. Last night I was trying to do some test shots outside. Its cold up here in Northern Ontario right now, (around -20 Celsius). So I head out, snap a couple shots, and then my camera doesn't want to take pictures anymore. The camera itself was working fine, it just wouldn't take a photo (with or without the flash). When I tried to use the flash, the camera would say it was "busy". So after maybe 10 minutes of trying I give up and head in. Which brings me to my second question.

2. I understand that condensation is something you have to be careful of when shooting in the winter. I plan on using silica gel packs and ziploc bags for longer shoots outside, in order to prevent any condensation. This time however, since it was a short time frame, I didn't bother slowly warming it up or putting it in a ziploc bag. I posted my question on a different photography site, and some folks there seemed to think its possible to damage the cam in that short time frame.

Any suggestions for my first problem? How big of an issue is condensation REALLY.

Thanks