What Causes Soreness And Bruising On The Thumb?

Hello. Earlier today when I was picking up a heavy bag by its strap the strap slipped and pulled my thumb backwards. All of the joints in my thumb popped (I think) and it hurt quite a bit. All day it has been super stiff and very sore. It also pops when I try to move it. Lastly, there is a small bruise right off the side and the whole thing is red and kind of puffy. What do you think this is?