poorly mouse
This may sem a bit dumb but............
if it's wireless, have you changed the batteries? also try and reset the mouse to the adapter (there'll be a little button underneath the mouse somewhere)
another thought, try adjusting the interval between clicks (for double clicking) if that's where the problem lies. I have found that, on occasion after an update, my pc or lapatop is expecting a longer interval between clicks than I give.
good luck