Think I hit something?
 

Well basically last night I cut and it wasn't really that deep but inside the cut I could see something moving it was like pulsating if that make sense? the blood was pouring out in a steady flow and it was dark red. Its ok now. Stopped bleeding after about ten mins but it was down to fat. What should I do?

The thing you saw pulsating was probably an artery/artierole but as you said it was a dark red steady flow it sounds like you didn't hit that and you probably got a capillary/venule (little vein) with it stopping within 10mins. As it was down to fat it should have been stitched really so I'd go to a+e/ a walk in centre to get it lookedat depending what time you cut depends whether they'll stitch as many doctors/nurses usually don't stitch after 8hrs but depending on the severity of it and it's position they will stitch later. Even if they don't stitch it it is worth getting it checked over so they can clean it and put a dressing on it