I agree, it definitely doesn't sound like social anxiety to me. Though I'm no expert. I have a bit of social anxiety and it's more like being self-conscious about how you will be perceived in social situations, not knowing what to say, obsessing about what you will say, or what you said, or who you will have to see, talk to, engage with, and being afraid of new situations with new people. (I'm sure there's a lot more to it but those are some of the things that I wrestle with from time to time, though it's relatively new for me.)
What you described about not really caring how a person is doing or if you interact with strangers? I feel the same way most of the time. I've got my own **** going on. I don't really have the time or energy to put into it. Mostly I don't even think about it. I don't feel anxious about it, though, except I do tend to judge myself about not being more considerate, caring, or compassionate.
What you're talking about, the fear of things changing suddenly, does sound like anxiety, but not really a specific kind. Everyone's anxiety takes a different form. You are lucky in that you can recognize it as irrational, even though it does take a lot out of you to engage in an appropriate response to the actual circumstance; I'm the same way dealing with my symptoms, though lately when I'm symptomatic I just end up staying at home because I am tired of expending all of the energy and effort it takes to give a damn about having to shield myself.
Hopefully things improve for you.