Help with spot healing brush

I am honestly not sure exactly what option/button I clicked inadvertently, but now whenever I try to use the spot healing bruch (even after doing a reset tool) I get the message on my image that says ' Alt-click to define a source point to be used to repair the image' .   What did I click and/or how do I get back to being able to use the spot healing brush option?  Thank you for any help you can offer.