This happend to my last batch as well. Luckily I have several spare airlocks and a bucket of StarSan handy to sanitize :D. I normally use blow off's on bigger ale's but not for smaller OG batches.
I would suggest keeping some spare's handy if your not doing a blow off.
Seeing as I cant Google a Homebrew question without finding a thead on this wonderous forum I figured this was a good place to begin my learning.
A post-emptive thank you to all of the wonderful people who have already answered so many of my neophyte questions is in order so:
ThankS! :mug: