No that's perfect weight for your height, I'm five foot nine and weigh 11 stone so I think you're fine where you're at :)
No it isn't. I went to my doctors the other day and had to be weighed and measureed I'm 5'8 and am 10 stone she said I was exactly what I needed to be .. I don't need to loose any weight of put any on. So to me you sound pretty healthy (: