Don't worry too much. You can't be that bad or you wouldn't have passed. Just plan well, make sure your headings are correct, it will come with practise. I always found a longer route worked out better than a shorter one, more time to settle down. Don't buy a GPS till you have got it right without.
Fly with another more experienced pilot is also an option. It seems to come more naturally to some people, I like you found it difficult.