It might be easier if you pop the yoyo up in a different manner. When I was learning it, I found it was much easier to get the timing and momentum of motion down when I would let the yoyo string hang off my non-throw hand, and pull the string away with your throw hand so that the yoyo lifts up, with your throw hand already in position to whip. For example, I do it like mentioned in the following video.
Break it down into steps. First practice popping it up and catching the string. Then once you get comfortable with that, then work on trying to catch the yoyo. Then after you get used to catching it, you can add the fancy stuff, and find different ways to get fancy.