Every mm in diameter that the pearls increase in size doubles the weight of the pearl. So if you're used to wearing 7 mm pearls, then 8 mm will weigh twice as much. When I first got my natural white Hanadama rope, they were 8 mm and I was used to a rope of 6.5 mm pearls. Boy those Hanadamas felt heavy. But I got used to them. Now I wear ropes much heavier, because PSS (pearl shrinkage syndrome) set in, and now I can't get them big enough.
If you're not feeling the natural white Hanadamas, try the regular pinked ones. You may find them more flattering against your skin tone. Try metallics and Freshadamas. They all have a different look, although the weight will be the same for the same size pearls.