overdo, overdue

Overdo or overdo means to tire or wear yourself out working, partying, or at anything--
I hope he doesn't overdo it this weekend. He was tired all week.
Her doctor told her to be careful not to overdo it. 
Overdo also means to go to extremes--too much, too many, too anything--
Get some decorations for the office, but don't overdo it.
Don't ask her to help with the party. She has a tendency to overdo things.

Overdue or overdue ( rhymes with overdo ) means late, or after the agreed upon or expected date, literally or figuratively--
My library books are overdue. I'll have to pay a fine.
His comeuppance was long overdue, according to his co-workers.

Now that you know that, you can say--
"Let's not overdo it with the overdue library fines this time. We owe a small fortune."