Overflowing fermentation

After finishing my most recent all grain batch on Saturday, I had 6.5 - 7 gallons of fermentable wort. Because of this, I used a 7.5 gallon bucket for the fermentation. This morning I went to check and the airlock was filled with beer, and there was beer all over the lid of the bucket. I was wondering if I should be worried about my brew, and take any steps aside from replacing the airlock with a small blowoff tube.

Clean the lid off, attach a blow off tube. There is so much CO2 forming in your beer right now, that nothing bad is going to happen to it.