So I have been hoping for a first in my second year but due to family stresses I cracked and I achieved an overall grade of 2.1 high. I was 1 point away from a first.
My course is 30% second year 70% third year. Will this hinder my chances badly to get a first overall in my degree?
You got (I assume) 69 in second year, so getting 70 in third year leaves you with a final grade of 69.7. Depending on your uni, but very commonly, this is rounded up to 70, and you'll get a First.
Little to no effect on your future at all tbh - at the end of the day it's just passing some exams and is about as far from what you'd be doing in an actual job as possible (bar vocational degrees such as medicine).
Experience counts for a lot more than a degree nowadays.