Welcome to Webmasterworld!
I'not familiar with that message, perhaps it's related to the Budget Optimiser. As it's still a long way to go till the end of the month you probably don't want to pause your campaigns all this time.
You say your daily budget is fairly high, but the proper question is: do you reach it almost daily? Set the daily budget (or monthly budget if you insist on using the BO) as high as you're comfortable with, but not higher then that.
Hope it helps!