Are you flying a C172 with mechanical trim (ie) the standard Cessna wheel, or have you got electric trim? (not sure of this, but believe there are some out there with electric trim?).
Sorry if this sounds patronising, but are you
sure you'd retracted flaps on that particular roller, as trim would be way out of kilter if you'd missed them. I'm a 170 hr PPL and I have still been known to miss the flaps....
