Hi everyone, I haven't been diagnosed bordeline (yet!)but I struggle with severe abandonment issues so I came here for advice since you'll know what I'm talking about. 
I have two best friends and one of them went to Scotland to study. Before that she had little time to meet with two of us, but we understood since she had to take care of grandparents. We talked a lot on messenger though. She is quite important to me since she was supportive during period when my mom was ill and after she died. She's one of the two closest people to me. 
Now it's almost a month since she went abroad. At the beginning everything was nice, we had video calls - late in the evening since she was busy, but still. She met some great people there in dorm and I was happy for her since she was scared to be there all alone. They seem to spend a lot of time together. 
I understood and nothing alarmed me until my other best friend pointed out she didn't text us for few days already. I tried to have this new attitude this year that"just because you don't text often or don't respond doesn't mean you don't care" since it was driving me crazy and I used to constantly check if someone is active etc. Anyway this triggered my abandonment issues.
We asked her how is she since she's not texting much, she responded 2 days later that she's fine but busy. Now it's getting ridiculous since we're going to fly and visit her this weekend and we need adress information for covid restrictions and such, but she only texted she'll reply later, but she still didn't. I saw on instagram she spent all day with new people. 
I'm trying to understand and not freak out, but it's hard - one of my ex best friends ditched me this exact way - went to study abroad, stopped contact. And my other best friend has abandonment issues too, but she reacts by being passive aggresive or ditching people. I'm super scared of her ditching the friend in Scotland or the friend ditching us...these two are one of the most important people in my life and imagining that our trio could break makes me depressed already.
I have a pattern of losing friends and usually I don't do much to lose them, but I don't try to keep them when they start slipping away. I am so devastated by it that I freeze and they're gone. I'm scared it will be like that again.