Pms vs pregnancy cramps

I know each individual is different, but could you tell the difference between cramps.. knowing AF was on the way vs before finding out you were pregnant? I feel like this time around it doesn't feel like regular AF cramps, but just a very consistent pressure throughout the day at times. Im on cycle day 30..where as my cycles are 28 days long. It is my first month off bc, and i did take a test at 13 dpo (2 days ago) and came back negative. Any suggestions, thoughts or ideas welcome