I suffer from this in general. I throw the first song of an album on, and before it's over, I've got some other album I'd rather listen to. I'll throw a show/movie on streaming and immediately regret finalizing a choice and go back to browsing.

Like others said - pick up the next book! And maybe once that one is done you'll have a hankering to go back and finish the previous one!

Just started reading again late last year. Set a goal this year for 24 books. 1 every two weeks, same as you. Am on track to do so, which is exciting. Have had to sqeeze some short reads in to pad my stats after little lapses, but have read some bigger ones as well (Monte Cristo, Brothers Karamazov, I'm 2/3 of the way through East of Eden). Average page count probably 300 for the year.