Am I pregnant?

Recently ive been feeling sick and my discharge has been clear and there has been a lot of it (sorry for TMI).
 I also haven't been on my period since around April (I don't know the exact date as I fail to keep up!) 
However, I'm currently 2 weeks away from finishing my last year of my a-levels. I say this as I'm not sure whether this has delayed my period as stress has delayed my periods before. 
Just thought I'd ask around on here as I'm fresking out!