I've been having dreams that i can remember latley!?

So For the past four nights i have been having dreams that i could remember . The first two dreams weren't scary. the first one had my crush in it and it was just a really comforting dream. and the second one was kinda weird because it was about this creature being in a lake but it wasn't scaru because nothing happened to me it was just strange. and the third one had a guy that i have never seen before in my life and he asked me out and it was a comforting dream also. But the fourth one was kinda scary because it was this guy that i have never seen before and he went syco and started hurting people (my brother , my dad , and me ect. ) and i woke up scared. so i kinda want to know why i have been remembering my dreams latley because i usually don't. Sorry for all of the details and misspelling , im kinda in a hurry! (: