What was Eren's vision about? I can't believe I missed this three times. I went back to the beginning of AoT in episode 1 and noticed these scenes that occurred at the beginning of the episode. Eren is having some type of daydream or nightmare before waking suddenly with Mikasa leaning over him. Here are the still shots of it.

             

What exactly were these visions? Were they some type of compressed/hidden memories? What was the farm house we saw? I am also pretty sure this wasn't in the anime but manga answers are welcome also. ;)

Note: I couldn't find a video link to give but there is a animated GIF version of it that I made here. Also helpful but it is quite easy to see the scene if you want to since it occurs straight after the opening of AoT in episode 1.
I agree with @Maroon. It's basically just a foreshadowing dream/bad feeling he had which combined his existing knowledge with his aspirations/dreams.  

However he does have legitimate flashbacks/dreams he doesn't know anything about later in the show/manga and discovering what it all means is part of the plot. He also keeps dreaming about a "female" he doesn't know.  His memory is hazy, and there are 


   the lost 3 years when his father experimented on him 


which I feel they will reveal over time. He also probably has memories/dream issues associated with 


   being the controller 


though it wasn't revealed if he became that 


   during the 3 year break or was like that before,


which could impact whether his dreams were induced by or related to it.