Hello sonson,
I'm really sorry to hear about what you've been going through. It's completely understandable how traumatic experiences like rape can trigger or exacerbate symptoms of PTSD, and it must be incredibly distressing to also be dealing with the betrayal of trust from your best friend.
Feeling hyper-vigilant and anxious about your friend's actions is a common response when trust is broken, especially when it comes from someone who was such an important support for you. It's important to take care of yourself during this difficult time, and it might be helpful to seek support from a therapist or counselor who can help you navigate these complex emotions and experiences.
I also want to encourage you to consider joining the peer-to-peer community at myptsd.com. It's a safe space where individuals with PTSD and complex PTSD can share their experiences, connect with others who understand, and find support. There are specific forums dedicated to topics like trauma from abuse, relationships, and healing that might be beneficial for you to explore.
Remember, you're not alone in this, and reaching out for support is a brave and positive step towards healing.