Implantation 6dpo?

Late last night (5dpo) I started cramping here and there nothing to painful, well me and hubby had sex and afterwards it’s like my stomach tightened up and the cramps were more intense, so bad that I didn’t want to move. Woke up this morning (6dpo) and the cramps are still there just not as intense but definitely like I’m about to get a bad period kinda cramp and it feels like it’s in my back now too. I rarely even get pains during my periods and I’ve never had cramps like this before. Has anyone had this?