Helppp

I'm 19 years old and me and my bf had sex on two of my fertile days in the window thing and he came in me... My period was due on the 1st, I already took 3 pregnancy tests because i was scared 3 and 2 days before my period was due and they were negative but now it's the 3rd and it isn't here yet, as far as I recall I'm usually on time or early... Should I be concerned? I'm getting really worried I'm not ready for a child yet ;/ I can't take a test ATM because I'm in new Zealand visiting my Nana with my mum and I won't have any time without them so I don't know what to do... How likely do you think it is that I'm pregnant? I was feeling nauseous all last week and my boobs hurt now...