The Other Day
The previous approximate was the previous approximate time, which is recently or the other day.
The reading is the kun'yomi vocab readings of the two kanji. That's 先 and 頃 (the reading you learned) put together. The 頃 is the rendaku'd version, ごろ so be careful.
We’d been good friends until just recently, but he suddenly grew really cold toward me. I don’t understand why.