5 days late, and white discharge instead of period...

I'm 18 and sexually active. I've had my period on time (Max 1 day late) for the past year or so since I have started keeping a record. My last period ended on august 5th and was due again on 26th of august. Halfway through my cycle I felt like I have ovulated but I have also bled lightly for two days (on Wednesday the 14th and Thursday the 15th). I am now 5 days late and I'm getting a slight white vaginal discharge every time I think I'm having my period. Today (on day 5 of being late) I've taken 2 hpts and they were both negative. I've had protected sex all the time except for once (it was either before or after my ovulation, I can't remember exactly when, but my boyfriend never came. It was just thrusting and he regularly pulled out to wipe off any sign of pre-cum). I'm really worried and don't know what all this means, as its a Friday I can't see a doctor until Monday and I'm really stressing out, could there be a reason other than pregnancy as an explanation to why all of this is happening?