i completely agree with Mike, Terry
the actual weight difference between a 5wt and 7wt, both rod and fly line is just a few wee grams.
sure, the 7 will feel a bit 'heavier' but that 'heavy' is mostly in the mind.
this is very common among casters of all levels and i don't have a clue as for the why...
(actually, my thoughts go towards the higher-rated rod being usually thicker than a lighter rod and that extra 'weight' felt is air resistance as the rod is moved back and forth throughout the cast. but again, that's just a thought)
so, back off the force, relax and think about
smoooooooooooooth casting and you'll be just fine. promise
cheers,
marc