I was dueling a friend(Priest) and he was being annoying and not attacking me and kept casting the bubble on himself so I couldn't hurt him so I tried to end the duel by using Drain Life on myself and when I was almost at 0 health it wouldn't let me use Drain Life anymore and the word "Fizzled" kept appearing on my screen.

Does anyone know what this means? xD

fizzled means ur loc is exhasuted u need to get into a inn and rest for about 3 or four days
come bak then ull be prepared
same thing happened to me and i just rest for 4-5 days and it never fizzle never came bak

You don't get fizzled from casting DrainLife, quite the opposite actually.

If you get the "fizzled" warning on your screen, it's because your health is too low to use either Life Tap or Health Funnel.

Also, you can't cast Drain Life on yourself. Best way to kill yourself is to Life Tap 'till fizzled, then cast Hellfire. Remember to remove your Fel Armor otherwise you won't die that easily.