Irregular?

Soo I got my AF December 16 for 6 days which is normal but then again when it was suppose to be my fertile days, December 29&30 it only lasted 2 days and was super light. We've been trying to conceive for a few months now & right now I feel so moody & constipated, such a backache nauseated & sore boobs. I'm wondering if anyone else has had this happened & still bled, if I should take a test? Or wait and see when it comes this month. So confused with what's going on in my body. With my first son i don't think it felt like this, I was obviously pregnant & knew it right away.