Just wanted to update and say thank you for your encouraging words.
I have settled more into my work as an independent RN and am learning an incredible amount each shift from the other RNs on the unit. I continue to ask questions non-stop, have people review my calculations, and triple or quadruple check my fluids (among other things). Time-management is still a struggle -- I am always running around like crazy, but I have a better understanding of the "flow" of the 12 hour shift and I even get a break sometimes now!
I had a dejavu moment giving report yesterday -- it was the same RN who had discovered my mistake, and the patient had the same fluid running (D5 half). Even though I check and re-check like crazy, I still had one of those heart-pounding moments of worry when she went into the room...
It was all good!