load off one's mind, a
Relief from a mental burden or anxiety, as in Good news about the baby took a load off my mind. This expression uses load in the sense of “a figurative burden.” [Mid-1800s]
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.