Should I just give up on my friendship?

Me and my friend Anna have been friends for years, we were best friends all through high school. The kind of friends that are completely open with each other and even if we got mad, we forgave the other right away because our friendship was too important to risk over an argument. We even stayed really close after graduation, and got together almost every week even going to college 2 hours away. but now Anna has gotten a new boyfriend that I don't like that she thinks she is going to marry and she has gotten a new job at a gas station and has started to change for the worse. She is getting deeper and deeper into some really bad stuff and doesn't want to talk to me about it. In fact, I'm not sure I even want to talk to her anymore either. She seems like a completely different person and It's like she forgot everything we have been through together. I feel like I am the only one trying to keep us friends anymore, and I'm wondering if I should just give up?