Confused and Worried...

This may end up being a long post and it might not make much sense but
I need to clear my head and get this stuff down before I go crazy.

Do I love her? What is love? Is it just sexual attraction combined
with adoration and common interests? The sexual attraction is there,
no doubt. I adore everything about her. We both have similar views and
are motivated in the same way. Does that mean I love her? If I love
her why do I get jealous when she talks about the past? Am I jealous
of her past, or the people who shared her past. Do I resent the fact
that I was not a larger part of her life before now? Why do I lament
the fact that I will never share those experiences with her, I'll
never go through those things with her. Why can't I look toward the
future and embrace the experiences that we will share and deal with
and survive together? I want to be a part of her life and I already
am, why can't I convince myself of this? What will it take to be a
"part of her life"? Is there some definitive event that will solidify
my position in her life? Am I just afraid that I'm not a part of her
life because I think she will leave me? Am I just an episode in the
series of her life? Will I be broken and forgotten, left behind to die
writhing in the sun? Why can't I fucking relax and enjoy the time I
have with her? Am I so sure that she will reject me and discard me
that all this is necessary? Is rejection what this is all about? Do I
fear another rejection? Do I have so little faith in her that I think
she will abandon me for no reason? Why was I always rejected in the
first place? I really don't know what it is that would make me so
undesirable and disposable. The worst part about it is that I feel
disposable, that anyone could replace me at any moment. And not just
replace me, erase me. I feel forgettable. Insecurity is my secret
weakness. I think I hide it well, just not from myself. I'd like to
think I present myself as confident, albeit antisocial, and although
I'm insecure I really don't care what people think. I don't care what
most people think, just people I care about. I want to feel accepted
as the person I am and not just someone that everyone deals with until
they can get rid of me. I want to mean something and not just be in
the background, blending in. I want to be center stage every once in a
while, not because I need attention, but so I won't fade out of memory
and be just one of those guys from high school that no one can quite
remember exactly. I feel like it was too easy to exit everyone's life
for over a year. I feel too easily filed away into obscurity. Describe
yourself in one word: Insignificant.

I think I know now what's been bothering me. Thanks, this was helpful.
Now on to the hard part, dealing with these feelings of
insignificance.