6 day light period - now slight cramping and back pain ?

My period is ussually 4 heavy days with clots 5 th day I’m done for sure . This cycle was 6 days long - light like I didn’t even change my pad 3 times a day . Now that’s over I’m getting mild cramping and back pain like idk how to explain it it just feels weird . Did anybody experience this with a bfp ?