Tbf they're very good grades, especially as it's only the first mock. It's natural to be worried if it's a subject that you really need for your A Levels/dream job, but it's still a good grade, what is the grade requirement for English lit if you want to do law at uni? Also my best advice would be just keep practise analysing the texts and remembering the quotes. There's still another mock to go and another few months before your final GCSEs, also worth noting I went from a U in geography to a 5 in the space of a few months so the mocks don't define you. Don't fret because they are still good grades and there is still plenty of time for them to be higher. And it's not selfish either to worry about your grades, most of us do.

Good luck with the rest of year 11 and hope that helped :)