Cramps+late period+BFN

So the title says it all not to mention that my periods are irregular but I haven't missed a whole month since around Nov 2016. I stopped taking birth control pills back in April 2016.... my cramps feel literally like my period is going to start anytime. You know those really distinctive raw dull cramps... they have been on and off since the first week of April. Sore nipples on and off also since beginning of April only last for a day at a time. Could I be pregnant? I took a test last on April 14 got a BFN according to my somewhat however I can guesstimate my period was to be here anywhere between April 1-15......help