I have been on the pill for a long time now. I have had unprotected sex numerous times and I have never had a pregnancy scare.
However I am starting to worry now. My last period was very, very short and extremely light, almost as if it was barely there. I didn't think anything of it but now I am not due to get my period until next week and Monday I noticed a brown discharge which has now turned to red and is almost like a period. As of today I am having extremely bad stomach pains. I have also been very, very mood as well as emotional for the last 3 or 4 weeks and have been getting frequent headaches which is unusual.

Could I possibly be pregnant?