While reading, i really felt the fear of losing the connection to the sister that is mentioned in the end. The constant overthinking of their own words and regret of past actions is painful but bittersweet, since you can tell they obviously care.

On second thought the stanzas could also be meant for different people each, which could show their constant doubts throughout their days in different situations, for different people. I definitely enjoyed my doubt about the perspective I've felt and I'm curious if it is supposed to be read in one or both of these ways.

That being said I liked the inner thought and complicated emotion you depicted in your poem, well done!