Awe, this is not unusual! I can relate to so many of those fears, letting someone in, being too attached, being rejected, breaking down (crashing/failing), fear of sleep, not ever making real progress, judgement, and I've certainly been scared of never getting past flashbacks.

I also do fine in my day to day life- I have a good job, am doing well in school, work friends, family, etc. but yes, I would at times love to run off and get adopted by my T, lol, or start a whole new life somewhere.

It sounds like you are just in a very stressful period of your life right now, but this too shall pass. I try to counteract my fear with thoughts of Quan Yin, a Buddhist deity of compassion, I look at her little statue on my desk and remind myself I deserve compassion. I am a good person, doing my best, and my fears are a very human reaction to adversity, no need for me to judge myself or worry, but rather to treat myself gently and lovingly.

Have you mentioned these fears to your therapist?
Have you considered trying to counteract them by doing things to soothe yourself?
For me, sometimes those things are simple- wrapping up in a nice cozy quilt when all the "what ifs" get really loud, or putting on a comedy, or making some hot chocolate. Some are deeper, listening to reassuring/empowering visualizations, doing DBT to get through my bouts with really difficult emotions, including fear and anxiety. They all help some.

Another thing to remember: you are more resilient, more strong, than you probably think you are. Even if some of those fears are realized, they won't be the end of you! No doubt, you have already dealt with some type of adversity in the past, and yet you are here now, it didn't stop you, not for good!