Fellow BPD haver here. So, I often have episodes of extreme suicidal ideation, sometimes followed by episodes of total euphoria. One moment I'll be planning to hop off a bridge— the next I'm drinking and having a good time with my family.
While it's true that our emotions are heavily unregulated, random, and extreme — I do not believe it makes our desires any less valid. I do encourage the idea of waiting a bit to see if you're in a heavy episode, to avoid doing something you might not do outside of those circumstances, but there is also a reality I acknowledge:
BPD is lifelong. It can get better with treatment — and plenty of people lead normal lives after DBT therapy, but there is also a chance that it may not get better. That these tortuous, constantly fluctuating emotional extremes, could be there for the rest of our lives.
What we choose to do with that information is our personal responsibility. But no matter what, you are not crazy. You are struggling and that is okay. Your feelings are not invalid simply because they work differently than others'.