What’s going on with yellow books drop lately. I have been farming the same spot for days now and not a single one have dropped. How am I supposed to level my skills, if I don’t even get 1 book.

You're supposed to pay the $50USD for the p2w skill transfer dummy.
(No but seriously, even though i farm mostly in hadum now, the lack of any way to get yellow skillbook is kinda crappy. They gave us 11th skill, and my main has all level 5 skills except that one. Its still level 1... no way to level it up that i can see)

Last month I was able to get 1 every couple hours, last night I farmed for 10 hours straight with normal buff, advanced buff, hot time, lvl 72 goblins blessing, and a tri luck stone and only after 10 hours I finally found ONE yellow book. It's crazy. Newer players are gimped, our skills will never be as high as the players who started at launch when the yellow books dropped way more frequently. There's no way we'll ever be able to compete. Totally needs fixed. I've been playing non stop 24/7 on my main for 2 months and only last night finished leveling all my skills to level TWO and that only happened because I managed to get a few yellow books spending 15k ruins tablets, and still only got like 4 books. It's RIDICULOUS. 

totaly agree. Yellow skillbooks do not drop anymore anywhere.... most of my guild has like lvl 7 skills while im stuck on lvl 3

Taphtar Hill and Basilisk Altar next to violent move. Basically any map in West Valencia that doesn't have Red Gear drops give you the best skillbooks drop rates.