Antonyms for the phrase "take a load off" would be to "add a load on" or "pick up the load." These phrases would suggest the opposite of relaxing or taking a break, and instead imply an increase in responsibilities and tasks. Another antonym could be "stay on your toes," meaning to remain alert and ready for action. Alternatively, "keep pushing" or "stay busy" would indicate the opposite of taking a break and instead working hard to accomplish tasks. It is important to find a balance between productive work and rest, as too much of either can be detrimental to overall well-being.