By counting the row 1 sts, 19 should be correct. Maybe it will help to spell out the entire first row...k2, yo, k1, yo twice, k1, yo twice, k1, yo, k1, k2, yo, k1, yo twice, k1, yo twice, k1, yo, k1, k2, yo, k1, yo twice, k1, yo twice, k1, yo, k2
One thing that might throw you off is YO twice...when you YO you aren't actually working a stitch...if you are then that would explain why you run out of sts
When you yarn over, you don't do anything with a stitch at all...you just put the yarn over the right needle then go to the next stitch. To do it twice you wrap around twice.
When you come to it again on the next row it acts as a new stitch and creates the holes that make a lace pattern. In your case you might treat it as two new sts on the next row since you did it twice. Depends on the pattern.