Happy to help!
You should look at the TIPP skill set from DBT, it's specifically designed to treat BPD people and help them relax and soothe distressing moments.
Here you go:
T: Temperature
Similar to one of the previous techniques that we worked on, the first steps works by changing the temperature.
Cooler temperatures decrease your heart rate (which is usually faster when we are emotionally overwhelmed). You can either splash your face with cold water, take a cold (but not too cold) shower, or if the weather outside is chilly you can go outside for a walk. Another idea is to take an ice cube and hold it in your hand or rub your face with it.
Higher temperatures increase your heart rate (which is usually lower when you feel depressed, sad, or anxious). You can take a hot bath, nestle up in a blanket, go outside on a hot day, or drinking a warm tea.
Note, be smart about it. You don't need to go full
Wim Hof. Cold exposure can make your blood pressure drop, and heat exposure can raise your blood pressure. If you have a medical condition where this could be a problem, skip this step or consult your physician.
I: Intense Exercise
When you have a built-up energy as a result of experiencing overwhelming emotions, it can be a really good idea to spend this energy by doing a cardio work-out. It doesn't have to be anything fancy - you don't need special equipment or expensive membership in a gym. Simply get on your feet and do one of the following: go for a run around the block, do jumping jacks in your room, go outside and walk fast. You can also try jumping rope, dancing or lifting weights (if you already have them). Do this for 10-15 minutes but don't overdo it. When you spend that conserved energy you will feel more tired and your overwhelming emotions will become more balanced.
P: Paced Breathing
In order to reduce the physical manifestation of the overwhelming emotions you feel (for e.g. increased heart rate, flushed face, dry mouth, sweating etc.) it helps to try to control your breathing so that its rate will eventually decrease. Try the following technique: breathe in deeply through your nose (abdominal breathing) for four seconds and then breathe out through your mouth (for six seconds). Do this for 1-2 minutes.
P: Progressive Muscle Relaxation
In order to relax the tense muscles in our body while we are experiencing extreme emotions, you can try progressive muscle relaxation. You can do this from a seated position. Start with the top of your body - become aware of your muscles and the upper back and deliberately tighten them for five seconds. Then let go - you should feel the region loosening up. Keep doing this with your arms, your abdominal and back muscles, your bottom muscles, thighs and upper legs and calves. This is a great way for your body to let go of the excessive energy that has built up with the overwhelming emotions.
don't forget that. As for getting help, have you got a therapist? Been to your doctor recently? Are you on meds for your BPD? Sending love and light 
