Is Calculus (dental) removal bad for the teeth?!

I have problem with Calculus on my teeth. The peculiar thing is I'm not a smoker nor passionate coffee drinker. As far as I know they are the main causers of this phenomena. I go every 7 months on Calculus cleaning at my dentist. But during the procedure my gum is bleeding abnormally, and after the procedure I feel my teeth very fragile. Is that normal? However, the main question is: Do I have to do every 7 months Calculus removal, and are there any possibilities that the removal is destroying the enamel of my teeth, is it making my teeth thinner and more keen on caries?
Thank you.