Why do I have slow healing wounds?

I am a really clumsy person and I just fall all the time and get cuts and scrapes everywhere. About 3 weeks ago I gashed open my toe on a nail that wasn't hammered in all the way. My doctor said that by now a new layer of skin should be growing over it but it's just like a gaping hole, it doesn't hurt or anything though. I've always had this problem my whole life. Like, typically it takes six weeks for a cut to heal completely but for me it's usually 8 or 9.. Is there something wrong with me? Also, I don't scar very easily. I don't know if that effects it or anything.. Help?