pregnant or other causes of a late/missed period

Safe sex:
-I'm on birth control (started mid November)
-I've used condoms every time I have sex 
-He doesn't finish inside me 
So, 
-my period is 6 days late 
BUT 
-I have white+clear discharge 
-I recently had winter break (so schedule changed a bit)
-I have been very, very stressed out 
What are the chances of me being pregnant vs just my period being screwed up because of other things?