Losing my line when down on the shot

[mr.fine]

When I do my walk in, I fixed my eyes on the object ball. When I’m initially down on the shot with my eyes still on the object ball, my line still looks good. But when I glance back on the white to check where my cue tip is pointing, then I glance back on the object ball again, I feel like I lost my line, feeling like I’m either missing right or left. Anyone experienced this before?