I totally understand your frustrating. When I was a new grad everyone one else finished orientation in three months and it took me five! I felt like I should quit and I cried at work twice because I was so confused on what I was doing wrong.
Looking back the root of the issue was that I lacked confidence. The catch 22 was that the longer they wanted to orient me, the less confidence I had! And every time we would meet in the managers office, I would always get a list of things that I was doing wrong. On one of the final meetings, the manager said if I couldn’t make it in a week, I would be terminated. I say this to say, I understand what it’s like to feel like you’re walking on eggshells and to feel like everyone is watching you and that if you make any mistake (which we naturally do when we are nursing/learning) that you’ll be fired. It is A LOT of stress and it messes with your confidence and now instead of focusing on learning, you’re worried and stressed. I understand completely and I also understand what it’s like to just want to jump the gun and quit before you “get terminated”.
Since I’ve been in your situation before, the best advice that I can give you is to not give up. Take the extension, it truly is a blessing. If you’re able to change preceptors, I would do it and just say “she was great but I know precepting is stressful and I wanted to give her a break plus I want to be exposed to how other nurses run their shift” (every nurse runs it differently and another nurses style may sync better with yours). I know when I’m being precepted I need someone that is very organized for others that may be annoying.
Take the extension, the pressure makes you a better nurse. By the time I finished my super long orientation, I was one of the best nurses on the floor. My time management and critical thinking was excellent and my patient care was as well. And I know that was because I was working 10x as hard as my residential cohorts because eyes were always on me to catch me making a mistake and I had a much longer orientation than they did.