I bleed from my gums when I floss?

I bleed from my gums when i floss on one side of my moth, I only bleed from my bottom right gums, and it only happens if i floss on that side and/or if i brush to hard.

I have had this for a year now i think and after haing for some months i went to the dentist and they told my gums were perfectly healthy and they didn't see anything wrong. When i bleed, those times i do floss on that side (very rarely) i do it for just some seconds. So i dont bleed for long, maybe 30 sec or so.

Anyone that has experienced something similar that might know what it can be?
I bleed from my gums when I floss?
Post Opinion