If you're feeling stuck in the middle of Act II, like you're unsure where to take your protagonist next, go back to your outline (though I would say if you're stuck in the middle of Act II then you never really had an outline to begin with - no offense.)
Check your essential beats: your jump into the Whole New World of Act II; your first Reality Check around the 37% mark; and ask what their ultimate goal is, and whether or not they achieve it. Then use a mirror technique: If your story has a (relatively) happy ending, find an accomplishment for your protagonist at the Midpoint that makes them feel like they're winning, then create their darkest point at the Pit of Despair at the end of Act II, before their big win at the Climactic Moment. Or if it's a Failure to Rise story, where your protagonist doesn't learn their lesson (or if they do, it's too late), then create a real challenge at the Midpoint, and then a big triumph at the Victory at the end of Act II, before the Climactic Moment when they lose.