There are so many reasons why you could be late it is really impossible to narrow it down without more information. Are you taking any medications and have you had any female problems int he past year and have you been pregnant before and so many more.
I would see the Dr and find out what is going on, have you lost or gained weight or had stressful issues lately?
The pain your having is a signal of sorts to let you know something is not right and you should check into it and find out what the problem is. Pain tells us that we need to pay attention.
Hello Klah, Welcome to MedHelp. You could have several things going on from just some nasty premenstrual cramps to endometriosis. I have to be honest and tell you that I do not have a lot of experience in OB/GYN issues.
Warm baths or a warm compress on you area of cramping may help. I know it did me after my D&C's. Also their are OTC medications that are usually effective for female issues. I would try one of them. Others will post with for information that I have and other suggestions. It is Sunday night and it tends to be a bit slow.
Please keep us updated and take care, Tuck