Well first of all, I realize this is a serious struggle for many who are clinically diagnosed with BPD. It's not by choice and it's not something anyone would wish for. But bear with me on this one..

I spent almost 4 years of my life in a relationship I found beautiful. I realized after all those years how we are stagnating and I literally felt like being trapped in something I don't want anymore. I broke up with him and the hell opened up. He started analysing my previous behaviour, accusing me of being dishonest, comparing me to his narcissistic mother, and soon enough he found my diagnosis: BPD. He is certified to do so by "long hours of reading about it, and watching Dr. Ramani on yt". It hit hard, I started to read into it a LOT, I even started believing what he was telling me for I could see the patterns there myself. 
But the thing is, it is such an complicated diagnosis, that even professionals have troubles with it. 

Not everyone who is lonely, seeking attention, has BPD.
Not everyone having emotional swings has BPD.
Not everyone who is unsure of themselves has BPD
Not everyone with those things combined has BPD.
Not everyone has a simple explanation for their behaviour.
I am a lonely 26 yo, with not so nice childhood, struggling to make a living in a foreign country since 4 years, all by myself - my family is in other country, trying to finish school in foreign language, there is so much pressure on me. I get depressed, I get emotional, I get insecure, I feel like I need security in someone. 

I opened up to him in previous years more than to anyone.. he knew my bad side, my secrets, my faulty thoughts (well everyone has a dark side), and he used everything against me at the end. Almost destroyed me in process... I am seeing a psychologist in my school but she says I am far away from having BPD since - even though not perfect - relationships with my family members and friends are pretty stable. 

I understood him, he was hurt and got whiney and needed desperately an explanation to why that happened, so he gave me a diagnosis and proceeded on telling me he is not mad at me for I can't do nothing for it, and he understands that, and he started giving me advice but in the same time shaming me for everything that happened during those years. 
I was scared to even wish him and his family marry Christmas for I knew he would accuse me of "hoovering". 
I can't even write to him to finally come get his stuff he wants back since months, to not be accused of something again. 

Now months after no contact with him I can see things more clearly, and boy how I understand people who got diagnosed, what a struggle every day must be for you guys, just the feeling of someone doubting you this much is unbearable.
Do you have any tips for me? Does anyone have a similar story and thats why they are on this channel? 
Looking forward to your opinions on this :)