That sounds about right. My first Med/Surg care plan took literally 20 hours! My whole weekend. My peers said it took them about the same. Still, I was determined to save some time and stop the craziness.
This may to obvious to some, but it took me a while to realize that I could use old care plans as resources for new ones. I did a lot of copying, pasting, and modifying. Saved me hours. A lot of abnormal lab rationales, meds, patho maps for infection, nursing dx goals and interventions, etc. are the same for different pts.
Also, instead of looking up drugs in my drug book and typing everything out, I went to drugs.com, searched the drug, and copied and pasted the drug info. Just cite the source.
I stopped slaving in the library doing care plans. Care plans, especially once you do a couple, are "busy work." I started doing all busy work in front of the tv. It didn't take me any more time and it made the experience a bit more pleasant.