Those really aren't poor grades...
GCSE's aren't even as important as people make them out to be. I got 1 A, 1 B, a gazillion C's and two D's. (well not literally, but I got quite a few) Anyway, I got a D in maths and still got through to college. Did decent in college and now I'm off to university with a D in maths and science GCSEs. Although my course isn't related to the two, it goes to show that gcse's aren't THAT important. Yeah some universities require you to have at least a C in core subjects, but you've already got them... In fact you've done good...
So, what exactly are you worried/complaining about?