Sounds like handle to me... I can't picture a plane the size we fly getting into ground effect so high at 8ft...
Since we are all pretty good at mentally compensating for upright level flight, I usually use inverted flight, and horizontal round eights and overheads to tell me whats going on with the handle instead.
When inverted, does it feel like you are fighting to keep the plane out of the ground, (feeding down, which is up inverted) ? Chances are you need to shorten the down line. (try small increments, 1/8" at a time or so)
In your eights, is your outside loop hard to keep from being taller than your inside? Insides tighten up? Again, different symptom, same problem, shorten your down line.
Overheads, same question, same answer.
Do you bobble or overcontrol your insides? same answer...
I'm skewing the examples all to one side here, but it works the other way too obviously.
Any who, those are the kinda things I look for.
Hope it helps,
EricV