What does this dream mean? WARNING:This dream is VERY graphic/disturbing?

So basically I took a nap earlier and I had such a strange dream. I'm currently seeing this guy "Ted" and I really like him (I'm not official/exclusive w/ him yet but things are getting quite serious between us) and I don't like anyone else, just him. So in my dream, I was laying in my bed and one of my Chemistry classmates "Melissa" comes up to me and lays down in bed with me. Next thing I know, we're having....well, sex. (I'm a girl too so I seriously have no idea how this was happening in the dream). I remember that I was enjoying myself, and later in the dream, I became pregnant and apparently it's Melissa's baby. I don't remember much else but I remember being very scared and I remember knowing I had to tell my parents and I think Melissa (in the dream) kept asking me for sex over and over again and I would decline and tell her that it was bad enough that I was pregnant but she kept insisting and got super angry. At the end of the dream I gave in and woke up.

In real life Melissa and I are chemistry lab partners .I actually don't know her that well but she's nice and I've never thought of her more than a friend/lab buddy (also I'm 100% straight and I've never had a lesbo crush/lesbo feelings/gf in my entire life). Melissa is also a popular student and I believe she is currently in a relationship but I'm not sure. What does this dream mean? It kinda freaked me out.