Caroline and Stefan made it down the aisle without a hitch on The Vampire Diarie's penultimate episode "We're Planning A June Wedding." But after the vows were exchanged, that's when all hell broke loose. During the reception, temporary Katherine surrogate, Kelly Donovan, crashed the wedding and blew up a house, nearly killing Bonnie and Caroline's twins. And, if that wasn't enough, Bonnie allowed the twins to siphon her magic to save them from the fire... and then she fainted. Bonnie used her magic, got the tired witch nosebleed, and fainted at the end of the episode, prompting many on Twitter to winder, is Bonnie really dead on The Vampire Diaries?
Bonnie used to suffer from nosebleeds after attempting particularly exhausting spells, and she always recovered. But, we know that witches have died from draining spells before (Grams comes to mind), and Bonnie doesn't have much magic left in her, so maybe the twins siphoned off just a bit too much. It's also important to note that Elena's confirmed return to The Vampire Diaries in the series finale could mean that Bonnie has to die. The two friends' lives are linked so that Elena won't wake up until Bonnie dies. If Elena is returning, then logic follows that Bonnie must die.
That said, I don't think Bonnie is dead. At least not yet, and certainly not for good. As stated above, this isn't the first time Bonnie has passed out from doing too much magic, and if she's rediscovering her powers, then it makes sense that it would exhaust her to the point of fainting. Furthermore, I know that Enzo told her they'd be together again (meaning when she died), but I don't think Bonnie is in a rush to join him. Finally, if Bonnie is, in fact dead, it might only be temporary. Stefan knows CPR, right?