What do you do when you are in the midst of a very strong emotional reaction? Many people with BPD experience urges to engage in a variety of unhealthy behaviors in an attempt to get rid of emotional pain. Self-harm, substance use, physical aggression, and other harmful habits often go hand-in-hand with strong feelings.
If you want to change the way you respond to strong emotions it will require some planning-- you can't wait until you are already upset, because it is too hard to think clearly when emotions are in control. Make a list of healthy coping behaviors that you can engage in when you are upset, and keep it with you at all times. The next time you notice a strong emotional reaction coming on, go straight to the list and pick a coping skill to try. If that one doesn't get you through, try the next thing on the list. Keep trying until the emotion has passed or the urge to engage in an unhealthy behavior has declined. For some ideas, use this list of healthy coping skills to get you started.
This technique is easier said than done, but with practice, you can start to make positive changes in your responses to strong feelings.