It happens to everybody. You are playing well, perhaps in one of the better hot streaks of your life. You are hitting the ball well, your short game is productive and your putter is hot. You are scoring well and you look forward to every trip to the golf course. As you are in the middle of another good round, you have a couple of tough shots that don't go your way. You start to mishit the ball -- and the next thing you know is that you have lost your rhythm.
Slow it down. When you have lost your swing rhythm, the only thing you want to do is get it back. You become anxious and lose your patience. As a result, you start to swing faster and quicker. Take a deep breath and exhale. Walk slowly between shots.
Take practice swings with your feet together if you are on the golf course. You won't be able to over-swing, and you'll lose your balance if you swing too quickly. Feel the rhythm of the practice swings and focus on that when you hit the ball. Don't think about the mechanics of your swing.
Go to the practice range and hit balls with your feet together before your next round. Take three or four back-and-forth practice swings between each shot. As you feel your rhythm return, take your normal stance and hit one ball. Then put your feet together and hit two balls. Alternate between feet together and a normal stance until you feel comfortable and confident hitting balls with your normal stance.