Usually I am so carried away by the negative thoughts, that when they come the thought of trying pratipaksha bhavana does not appear at all. What to do?
Pratipaksha bhavana is a teaching of Swami Sivananda. Whenever there are negative feelings or negative or bad thoughts, instead of continuing to think about it or brood over it you develop instantly a positive thought to replace the negative thought. That is called pratipaksha bhavana, cultivation of the opposite thought.
The negative thought is to be replaced by a good thought, bad feeling is to be replaced by good feeling, bad performance is to be replaced by good performance. Therefore, the journey from the restrictive and negative to the expansive and positive is known as pratipaksha bhavana.
When a negative thought comes to the mind and you become aware of it, then instead of trying to follow the trail of that thought into deeper negativity, you put on the brake and cultivate a positive thought to replace the negative one.
This is possible when there is awareness. Your question reflects that you are not aware of your responses and therefore you are not able to do pratipaksha bhavana. If you were aware of your responses then this situation would not happen.
Therefore, cultivate awareness of your responses rather than worrying about not being able to do it because you lost track.
Rather than trying to practise pratipaksha bhavana, don't worry about it, don't practise it, but initially cultivate that aspect of your life that will help you practise pratipaksha bhavana.
Things are simple but people make it complicated. There is a plate of food in front of you and you ask how to eat. You eat with your hand and mouth. If you ask how to eat the food it means that you have had no experience in eating food. Instead of watching the plate, you have to see your hand and use your hand. The food is not important; the hand is important. The food is in front of you, but you need to use your hand. What is more important in the eating process? Food or hand? The answer is hand.
Similarly in pratipaksha bhavana it is not necessary for you to instantly change your negative into positive. You can't do it. You have not been able to, because you were looking at the plate not at the hand. The application of the hand, using your hand, is awareness. If you can become aware of your mental response by cultivating the faculty of awareness, then the pratipaksha bhavana becomes easy. It is as simple as that.
—25 September 2016, Ganga Darshan, Munger