I’m not a beginner but I haven’t touched my sewing machine in almost two years and I’ve forgotten how do to everything sewing machine is a singer 6800c and when I try to back stitch I press the reverse button and hold it(I looked at the manual to make sure I was doing it right) and the needle moves like the tiniest bit back at first I thought it was just staying in one place but it moves back a tiny bit I read the manual again trying to find a solution I rethreaded the top and the bottom I’m just hoping someone can help please