Syncing Issues

[kanoots]

I have a N1E and have an SD card installed.  Today I plugged my nook into my laptop to add a few new side-loaded titles using Calibre.  There was no internet/wireless connection.  After I made the changes, ejected everything properly, and clicked on "Now Reading" to resume the B&N ebook I was halfway through reading, it wouldn't open.  I went back to the B&N bookshelf to open it there, but it asked me to download the book again which I couldn't do because of the lack of wireless service.  When I realized I might have a problem, I tried opening random books from both the B&N shelf and the My Documents shelf, yet none of the books would open.  What part of the process of hooking up the nook to my computer and adding side-loaded books changes the availability of my B&N book?  Why did the books not open?

Another issue (or perhaps they're related?) I had while doing this same process was that when I completely turned off my nook then turned it back on (after I'd realized my books weren't opening), my nook no longer listed any of the books that were on the memory card.  I went from 140+ pages to 7 in My Documents.  When I plugged it back into my computer and opened Calibre, all the books were still listed as being on my device.

What am I missing?  What happened with the sd card?    Is an internet connection required when making changes to the nook or sd card?  

When I got home and was able to use my wireless network, I managed to right all the wrongs.  All my books open, all my shelves are still the same, and I was able to re-sync my sd card to my library so that they all show up.  I don't want to go through this again!  I spent half the day without a book to read because of this glitch, and it was rather unpleasant.  I've looked through pages of help topics and haven't found anything related to my issue.  Please help!