My periods are usually 8-15 days apart. it's been 26 days sense my last period ended. i've been having cramps but no period. is my period late?

Not normal: It's not typical to have a period that is 8-15 days apart. It's likely that you are having some breakthrough bleeding. Can be normal for an 18 year old. My recommendation would be to keep a diary of your period and if you continue to have periods 8-15 days apart, see a gynecologist. You could have anemia and might benefit from cycle regulation. Good luck!