I was starting to sew something earlier with my sewing machine, because I've meant to but kept forgetting to take out my sewing machine. Did it today, and I'm just making a blanket. Something simple since I haven't really sewn yet. No decorative stitching or anything and... I'd start and the stitches would start going diagonal...?

Like...it'd start out ok, and then it's like as it started stitching it'd pull the fabric bit by bit over to the left so it'd start going diagonal

Have you adjusted your machine? Each one is different. Mine are on the top left hand side.