Thank you for your query at DoctorSpring.com
I understand your concern.
Firstly you're not pregnant. No matter what you read, the fact is no one can get pregnant without intercourse and ejaculation inside the female vagina. Considering your boyfriend didn't cum inside you, there is no question of pregnancy.
Now regarding your period, sometimes periods can be delayed even by a month or two, due to hormonal fluctuations or due to stress, e.t.c The brownish discharge could also be indicative of hormonal imbalance. I will advise you to wait for one more week and if you still don't get it, get a serum FSH, LH, estrogen and progesterone values tested along with a thyroid profile and follow it up with me.