you're brave for posting about strong and personal dreams here. If I were in your shoes, and these were my dreams, I would think about them something like this...
A lot of time in the dreams we will be with a big group and I will go to do something and she always stays back and later
I find myself wondering where she is and wanting her to be there. She'll get really catty with me or say things that just
upset me in general.
the premise seems literal to me, only instead going to school you just go with some group of people. Maybe her reaction in the dreams is something like the worst possible version of how you think she might feel about it. This doesn't imply there's any truth to it, since we are after all talking about your subconscious and not hers.
the other bit about you being in town and her not helping you. That one's kind of interesting because you are the one "left hanging". I won't guess at why that is but to my mind it still relates generally to the theme of concerns or worries about your connection.
I operate under the idea that a feeling has to be a part of you to arise in dreams, but that's me, I'm worried about being too forward so please take all this with as much salt as you see fit.
I'm also wondering what would happen if you talked to her about these dreams.
another question - now that you've done a year of this long distance thing, have you two talked about how its going for you? How you feel about it?
no pressure to answer
in any case, I wish you both well