Graduation woes

So i am currently doing my Masters.
My marks are so wishy washy due to a few issues here and there. They are not bad but nether are they as pleasing as i would like. I just want to know if a distinction in my dissertation will pull up my overall grade or not.
Please help i am so worried and so anxious

You need to read your course handbook, see how the various elements of the degree are weighted and graded, and then do the maths.