Hi, Jamie!

Don't beat yourself up. We all went through this phase you're going through. It is a very stressful time. It really is more of an extension of school except you don't have an official instructor to stand at your side all the time. You are truly "putting it all together" now. You have to be able to find resources on your own at this point. Hopefully, you have a preceptor and other staff nurses who are willing to take the time to show you tips and tricks.
Keep your textbooks within easy access because you will probably be needing to open them frequently still. I would hit my textbooks every time I got home from the hospital during my first year or so out of school. So, look up fever in the index and start re-reading on it. You are going to find that what you were seeing was a patient having chills. Her body temp was so low it was compensating by trying to raise her temperature--thus, chills. You didn't give her the fever, believe me. When I get chills it is so uncomfortable that I pull blankets around me--chills make you feel like the source of the cold is coming from the center of your body! I turn up the heat and wrap up in more than one blanket and I still feel cold. It's a very odd sensation. It is also not unusual for a patient to come back from surgery and experience a temperature spike. After all, the body has just experienced an invasion of some type and been under physical stress (re: Hans Selye's theory of stress). For this reason many post-op patients receive antibiotics in the immediate post-op period--many times started in the PARR. I would have raised the temperature in the room and given the lady blankets too.
As you become more proficient in performing an RNs job, your feelings of paranoia go away and your stress level decreases. For now, they are helping you to be careful in your practice until all these things become second nature to you. Hang in there!