I'm only 22, but I've been through something similar. I used to have a huge problem with people pleasing behavior. and even though I flunked out of DBT 8 months in, that is the one area where I really made progress.
I let a lot of people in the real world take advantage of me because I wanted to be liked and validated. Friends and partners alike. It was stupid.
Recently I'm starting to realize that an online friend I care very much about was probably using me too. At the time I thought he was someone who truly cared about me, and understood what I was going through. I ignored warnings from others that he was using me, and that he wasn't who I thought he was. Even though we didn't always get along, I thought he was one of my best friends and he meant a lot to me. Still does. but now with a sober mind I realize they who tried to warn me were probably right. I was a means to an end for him, and that hurts me really bad. I didn't wanna run away with him, but it's similar in that my BPD blinded me to what he was really all about and left me vulnerable. I'm still dealing with the hurt but time is making it easier.
Remember that you are not alone, and that you owe it to yourself to really get to know what someone is all about before emotionally investing in them, whether it's as a friend or more.