each person is unique, their reasons are unique as well. reasons to ctb, to write a note or even not writing one. maybe rush, idk. as I said: unique.
so sorry for your loss, I really do know what it is to be on that position and it's awful. if your relationship w that person was a good one, don't worry too much about this "issue". in any case, remember that past is past and you can do nothing to change it. we only have the present to act and modify things or not. I hope you get better and I hope you can reach a stage of a clear mind, you're probably in need for it. be well