The icon stand for which spell. The small number on the spell is which cast, to track diminishing returns. So after the 3'rd you can't cast any more till the timer is reseted.

The left number is the duration of the spell, when it's 0.0 it's gone. The right number is the duration till the diminishing return will be reseted.

The green bar is the duration left on the spell. The white/grey is the duration till the diminishing return is reseted. The white/grey shows up when the spells is gone.