Sacrifice.
This is the occasion when the dreaded quality had to be out from
its passive nature. Issues like this are VERY common, but what
makes a survivable relationship against one who sinks to the
ocean-bed... is sacrifice, another level higher than
compromising.
Currently, there are several issues congregating and churning out a
whole chunk of chaos. You could begin by eliminating factors that
are against you, understanding your own situation/relationship
thoroughly and make alot of adjustment to your own relationship. Of
course, this will come to nothing if it is merely an effort on your
part - your gf has to be your other hand.
***
Is it a MUST for you to work a night job? (Because
we are talking about sacrificing for the relationship, do not tell
me why not her). If money is the issue, try to ride on the donkey
as you look for the horse: attempt to find a day job that pays you
equal or something. EVERYTHING has an alternative to it; problem is
whether you want to accept them anot. By eliminating time
distortion, you could save and devote precious time to rebuild your
relationship.
If I was to say that your relationship is gone for sure, what are
the chances you will end up with this other girl? Chances are, if
yes, it could affect your relationship unconsciously. With your
current lifestyle and stuff, this new girl could probably fit you
better. But does it mean 'better'? This is self discovery and
understanding to guard your own relationship from sudden shift of
feelings/etc without knowing why.
It's interesting when you state and stress that you two are merely
friends, but you included her in this Aunt Agony topic. It goes to
show that your barrier to external influence is waning.
To chat about your problems is good; but do not stop there. Talk is
level one; you have to go beyond communication and decide what you
two WANT to do with the relationship to improve it's lifespan,
quality or whatever. The issues I wrote above are things you have
to go through your mind and digest a little. Only then, you can
make choices for your relationship, to leave the crossroad and
embark a new journey.
Your Love is stagnant, not dying. Don't run into the latter.

Cheers