I can do this willingly, I think its called relaxing but its not exactly it.

I close my eyes, focus my eye sight basically into my head (kinda hurts after a while)
stare into the darkness
feel body parts pulsing, I feel like im fading away, as if I am becoming nothing, or a part of the earth.
Before I can get deeper I realize I gots to breathe.

How can I get myself to go deeper without passing out from lack of breathing?

Once you've relaxed your limbs try to make your breathing rhythmic and mantain it.

Many forms of meditation stress focussing on breathing.

But since it is sort of a semi-automatic thing, I doubt that you will ever literally "forget" to breath.

Enough carbon dioxide builds up in your system and a reflex will take over.