Hey there Jen, good to hear from you. HSP's aren't just sensitive folks, as in crying at a sad movie. And I think most are sensitive to a point. HSP's are hypersensitive to the world around them. The world just overwhelms them, and it certainly sounds like you.
I used to make lists for my days and I have come to realize that I can't schedule more than one or two tasks in a day. It has taken me some time to realize this. I am best when I just need to do one thing a day. At family get-togehters, afterward I am a mess for a week...need to hole up in the bedroom and do nothing. Its almost like sensory or nervous system overload.
If you get a chance, read the book that I spoke about in this thread. It will enlighten you. I believe she stated that this is about 20% of the population. I also think she said it has been added to the DSM as a diagnosis, but it has been awhile since I read the book.