Don't take the feedback personally, a lot of universities have anonymous marking so it isn't directed at you on a personal level, they can't tailor it to match their relationship with you so try not to take it to heart.
I did a degree is an unrelated subject to anything I had studied before and I have the same feeling of 'what have I let myself in for, I know nothing compared to the others!' but I just took it one assignment at a time and ended up getting through and onto a MSc as well. Your first year is a chance to learn about how you study best to make the most of it, depending on your course the first year won't be calculated in your final grade (do triple check this!) so use it as a chance to learn and prep for second and third year.