A state or feeling of being ready to fill an obvious void
Anticipation Expectation Receptivity Frustration Hunger ?
In psychology terms, I think you are describing Jakk Panksepp's SEEKING, but that term doesn't work well except as jargon.
You are in a Responsive state.
quick to respond or react appropriately or sympathetically
Anticipatory is the state of anticipating your opportunity. The joy of this frequently disappears once the opportunity is acquired and the true conditions are understood.