be in the thick of things

To be very busy; in the middle of or preoccupied with something or several things. Sorry I couldn't make it to your birthday lunch on Wednesday, I'm afraid I'm really in the thick of things at the moment. Even when you are in the thick of things, try to take a moment each day and take a deep, calming breath. I'm kind of in the thick of things right now, chasing two toddlers around. Can I call you back later?