My period is 6 days late now getting bad cramps and pain going down my leg. took a home test came negative. what could cause that?

Period coming?: Many people have those kind of symptoms for several days prior to the bleeding starting. Pre-period symptoms can also be worse if your period is late. Make sure you don't get any signs of infection, like fever. Use non-steroidal anti inflammatory medication (like ibufrofen) or heating pad for the discomfort. Get seen if it's not getting better soon.