sorry that happened :/ For the future you can give her her own space and pop a male in there when you wish to breed. The 2 males to one female isnt the best option i think... You only need one stud, but you can have a few females. I personally seperate them to thier own tanks so i know nothing odd will happen.
And you always want to rotate your females too, give each one about a month or so off with good feeding and care between litters. And really you should only expect about 3 or so litters from one female.
Also.. try to stay away from using older females... Because they can have problems birthing and they might start to have smaller litters. So its best to retire them.
Hope that helps!! ^^