Ah, the dread... The best way out is through. Don't try to make the nausea go away, don't try to deny it, and don't try to rationalize a reason not to feel it. instead, reframe it. It is not you becoming a pussy again; it's a symptom of the adrenaline response coming from your fear, precisely because you're doing hard things, not fleeing from them. Being a coward is about actions, not feelings, and your actions are that you continue to train. Excellent, young man.
Instead of listening to your body, talk back to it:
"I'm feeling nausea again. GOOD. That's the adrenaline. Adrenaline makes me stronger and tougher, and it gives me focus. This feeling means that I'm about to kick this set's ass."
Over time, the reframing will become the norm for you, and this carries over to a great many things. You'll learn to associate the symptom, not with fear, but with excitement.
Between your form checks and your posts on this board, Jukh, it is very encouraging to see a fellow learning these things so early in life. Some of us learned them far later in life, and a lot of (most?) people never learn them at all. Drive on!