Good enchanting combinations seem impossible

I've gone through stacks of lapis and hundreds of levels with no avail (not an exaggeration) to enchant a diamond sword with more than 2 enchantments including Looting. It did not used to be this difficult, and I'm not sure if this is because of the new Grindstone, but even with it, this is taking far too many resources to feel viable. 

Not sure if this is a bug, but this is so difficult nowadays compared to before, that it is very strange, and very frustrating.