Since no one mentioned it yet - Growlers are not rated for carbing beer!
Sure it can work, but it's a risk every time. Get some regular 12 or 22 oz bottles for next time. They are generally rated for 3+ volumes of CO2.
If you want to find out what happens when a growler explodes see:
There are a dozen similar threads if you search for them. Revvy has done a post on several of them that explains all the why nots.