I suspect that your problem is more related to the crank. If you rode for a while with a slightly loose crank, the movement would have worn the area where the spindle engages it. Once that happens the crank can move slightly forward and back with each revolution, creaking and working the bolt loose.
In all likelihood the BB is OK, but the aluminum arm is toast. For future reference, loose cranks are like dental decay, unless you respond and deal with it immediately it'll progress beyond repair.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.