I was looking to purchase some pearls earlier, but when I looked at the pearl shop the bonus pearls + black pearls deals are gone?

Yes the black pearls deal is over. The deal is only until 14th Jan 23:59

Thats really a bummer - now you feel kinda cheated when you only get white pearls...

Yeah kinda suck it ended on the 14th. I thought it was like a monthly thing

I suggest you check their Pearl Shop Update announcements whenever you are interested in some of the deals. Deadlines are shown there. Just so you don't get disappointed again

Yeah Pearl Abyss does that a lot, they will post a really good deal for a short time, then take it down for a while and put it back up without announcing it. They do this to drive up demand, so you snatch it up when it appears since you don't know when/if it'll be back, even though if it was permament you might just skip over it.

You can click the "purchase" button on pearls without actually buying them and that screen will tell you exactly when the special sale ends - if no end time is listed, it's permanent...until they decide to change it. 

Unpredictable sales is how you do these macro transactions, and PA is good at it.