[loramin]

Is there any possibility that they are there in your book, just on later pages?

Perhaps when you opened your spellbook to mem the new spells, you hit right a few times, advancing the spell book to page 20 (or some similar page)? If you started on a blank page, page 20 would have looked the same, so you easily could have memmed the spells ... but then when you camped and came back the spellbook went back to page 1, so it looked like your spells disappeared.

That would fit everything you described (eg. not being able to remem the spells), and it'd be easy to check: just open up your book and press right a bunch of times until you see your spells (then use right-click to move them back to the front).