Period one week late!

My period is usually a day or two early or late, but it is now over a week late! I took a cheapo test this morning but it was negative. I didn't even have sex until like 4 days before it was supposedly due... So I really don't think I could be pregnant anyways. I don't think it could be stress or medicine related either tho. I did have some crazy intense orgasms last week, could that set it back? lol meeep!