I have always had many floaters in my eyes but lately i have a very dark one in my left eye that i can see even when i close my eyes. retina tear?

Depends, See Eye MD: Although many floaters are benign, a new onset of larger or "different" floaters especially if accompanied by any light flashes or changes in vision can be a warning for retinal problems. Make sure not to rub the eye(s) and avoid any vigorous shaking of the head & eyes while arranging to see your eye MD. If the retina is involved, time is essential so don't put this off!