Nihilism vs. Existentialism

Here is a philosophical quesiton that I thought of as I was sitting on my throne this morning.

Am I a existentialist? That I exist, therefore I am? That I and my mind, my soul defines what I am and what people are (visvi) to me?

or am I a Nihilist? That I exit? So what in terms of eternity? That I, and people around us are so insignificant in eternity?

Lately, the nihilist in me is winning? or so I thought....

Aren't we all destined to perish in the sands of time? but then.....
shouldn't we at least go out in a big bang, at least to the people connecting to us in this sand of time?