What Causes Stomach Ache Along With Vaginal Bleeding?

Hello I have a quick question. Over the past 3 days I have been very sexually active and I have ensured to take my birth control and use condoms. However today I am experiencing some stomach pains and what felt like cramping the other day. Now, I see a little blood on my bath tissue and some slight discolouration in my pad. If I was pregnant it wouldn t show this early right? These articles make me paranoid.