Well the next chapter is titled "And That Is The Well To Live", so it about someone overcoming sucidal thoughts, so can it be about Natsu, could be contemplating just dying not that Igneel is gone?
Could be, but while I know Natsu will be devastated, I just don't see him go all suicidal just like that. I think if that happens it needs to be a slower build.
If not Natsu than who, I wouldn't be surprised if we go to some where else. Perhaps Minerva still depressed over the mistakes she had made, or any of the surviving 9 demons, I mean their whole purpose is no longer there, what is there left to live for?, my personnel hope is Sayla. Not only has Zeref said their whole purpose is gone, but her lover is dead. If she is still alive, she has all the reason in the world to just give up on life.