>>1177264>>1177365It is a natural feeling in your position. I wasn't comfortable with the plane until later in commercial single myself.
You are approaching it from a flight training aspect, and associate flying with flight training, which isn't always good. It is good to remember your training and what your instructors have taught you, but if you only perceive flying from the perspective of a student you are missing the point.
My advice is to go and rent on a quiet Sunday morning, select a location with no other traffic, and just dick around. Fly the plane, have some fun, make yourself smile. If you'd like, take a friend and share the fun with someone who isn't so familiar with flying, its always fun to give them an opportunity to do something they wouldn't normally. This will build confidence in both the plane and your abilities, and will help remove the mental block that separates the fun from flying.
As far as the little details like filling the tanks to the brim for a pattern flight, or doing a 2 hour preflight, you need to understand that flying is all about acceptable risk. Do I need 55 gallons of gas for an hour in the pattern? Do I need to inspect every rivet before considering my plane airworthy? These are experience-based questions, and you need to think like a commercial pilot. Any mechanical issue that is going to seriously jeopardize the safety of the flight will be readily apparent upon normal inspection, and those that aren't will most likely be very difficult to spot. Be adaptive and cognizant while flying, but don't panic over nothing. Think like a pilot, not a student.