Every time I lose all my energy to 0 poin, I quit the game then restart it and strangely it has come back to 100 (^_^")
I also can't get the seventh ending... but for the second ending : it's in Triss' route, can be achieved when your choices leads your MC to have no romantic feeling for Triss, and you accidentaly or even purposefully don't finish/reach the end of the maze. Hopefully it helps :)