Airgirl,
It can take a long time for the doubts to go away. Even after my PPL, the doubts were still there. In a way that was to the good because it kept my nose to the grindstone in carrying out the checks and doing a thorough flight plan. I started using airplanes to go places and the various
interesting situations that came up and were adequately handled eventually erased the doubts.
Overconfidence is the more dangerous condition.
One of the bugbears that is hard to lay to rest is: will I be able to do a proper forced landing landing if the engine breaks? -- presuming of course that you have arranged that it always has enough gas
When I did a checkout at one school after a long hiatus, I discovered that the instructors had a habit of declaring the engine lost after I had completed the down wind checks. This was to a demanding runway. The confidence level went up a few notches after doing a few of these and landing on the button each time
In gliders, your first outlanding is more demanding than your first solo as you really do have to think for yourself rather than just do what you have done dozens of times before.