I could really see something that's not there. If others see nothing of the sort, they're probably right.

Edit:
Just wanted to note that drug use could very well be a "result" of a borderline personality. But again, it could be something else completely, nothing related to your personality or . It's just the confusion, irritability, impulsivity, reactivity and changes in demeanour.

It could also just be being introspective yes, causing anxiety when your mood changes, making it erratic, like a mixed state.

How you (seem) to continuously struggle and be confused about your emotional state: really hope you find the right help, ways to manage, soon! Hope I didn't add to the confusion.

At any rate, thinking you are exaggerating or anything like that is nonsensical: if you struggle, there is a problem that needs fixing/managing.