What fills my veins?

I often wonder about my veins,
and whether they are filled with blood.
Science says it must be true,
but sometimes it seems there’s only pain,
and crushed glass and icy tears,
an unlikely combination bound by fear.
As well as paranoia and mistrust.
But if those are all there, there must be some,
like love, and joy, loyalty, and liberty,
things that cleanse my soul and give it back to me
brand new and for a while all is right,
until darkness hijacks my veins again.