Much the same experience here, including the difficulty with memory which I find to be the most insidious thing. What have you found helps it, if you don't mind me asking?
When I feel the doubt about past memories/decisions start to creep, I whip out my phone and make some brief notes (usually keep one document per trigger). I will just write a few bullet points detailing what facts I am sure of right now along with the reassurances I am telling myself in that moment.
Then, next time it happens I open the same note, read my previous thoughts and relax into it knowing I’ve been here before.
I suppose it’s just an anxiety journal, nothing novel, but it works for me. Over time as I accumulate more facts the effect sort of compounds and simply knowing I’ve got the notes is enough to push the anxiety away.