You have indeed come to the right place. I am sure someone will be in a position to help you soon. Please don't panic !
I also find that Opera accumulates a large and ever growing quantity of data which eats up valuable memory space. The only solution I have found is to clear the data periodically in app settings. But this has one dawback in that clearing this multi-MB data also wipes all your speed dial entries which is a real pain.
An answer by an expert to solve this problem would be most appreciated.