A Terrifying Alien Encounter Memory Recall

Mid-October 1975. college dorm room between 1:00-1:30 a.m. study lamp on at desk near door to common hallway. Studying at desk; disconnect/lost time, then standing closer to room-width window to outer courtyard. Very little light outside in courtyard; could not see sky to determine weather. 

Window was on sixth of seven floors above ground, brick exterior wall w/ no ledges. Apparently saw an Alien with a large head width of my shoulders with sloping shoulders, motionless, just outside the window. Very large black eyes staring directly into mine; I could not look away. Visual sense of slow movement toward creature? at window, with no sense of walking toward it full body numbness. 

Initial reaction minimal was that the apparition represented as a "grey" alien, except for size (of the head and shoulders, the only part I could see), I could only look into its' eyes, and felt frightened, in a dreamlike state; I felt completely paralyzed and powerless. As I approached the window there was a vague motion of the creature(?)'s left shoulder, As I felt it was going to reach through the wall below the window to touch me, and my eyes unlocked just enough to note my shadow from the desk lamp against the wall and window screen. At that exact moment I felt terror I had not experienced before or since, and I moved almost instantly to the far end of the other (unoccupied) bed in the room and folded my knees up into a fetal position, with my head between them, and began screaming as I have not done before or since.

I don't know at this point if my eyes were open or closed, but I felt the sense that the Alien thing was either reaching into the room for me or even standing next to me. I simply was too terrified to look at it or anything else. I kept screaming seconds felt like minutes, and so forth, until people from my floor of the dorm began pounding on the (locked) door and yelling for me to open up asap. 

I began telling myself it was only a nightmare, over and over, and eventually gathered myself enough to move to the door and open it. I still couldn't stand to look toward the window. My R.A. resident assistant walked past me into the room, probably looking for evidence of violence and/ or drugs; he found nothing, and after grabbing me by the shoulders, he asked if I was feeling alright, and we started talking back and forth, echoing each other that it was only a nightmare, a really, really bad nightmare, which was the only way I could deal with it for a long, long time.

I am sorry to be so short on measurable details and long on the drama, but I've been watching a certain movie for the fourth time over the last several years, and the characters in this 'mockumentary' repeatedly talk about eyes at the window in a way which has always disturbed me, and as of today's viewing I am remembering it as if it was a real event, and feeling very shaky as a result; I've only mentioned it to one other person over the years, and then only in the context of a bad dream.

I need to mention here and now that I've been on social security disability for almost 25 years for bipolar disorder, for what it's worth I would also state that, based on illustrations I've come across in just the last year, I would describe the apparition, for want of a better word, as either a very large gray or a reptilian/gray hybrid, if there is such a thing. mufon cms # 116626 Florida U.S 10/15/75