Cycles do change from time to time, being, that our bodies change every few years . Stress doesn't help and can actually delay your period .
Wait a week at least, take a Pregnancy Test , they are only a $1.00 or you can go to several Free Clinic's and get Tested for free and given Condoms or Pills for FREE !!
Is there a reason you are having Unprotected Sex ?
Are you wanting to get Pregnant ?
If Not, then, find out if you Are or Not Pregnant.
If you are, you will miss your Period for another 8 months at least . And have a lifetime of Responsibility.
If Not Pregnant, get on Birth Control ,of Some kind, Pills, Nuva Ring, Norplant, or Condoms.
It is time to be Mature and take Responsibility. You and Only you are Responsible for your Protection against an Unwanted or Unplanned Pregnancy. No Protection, No Sex !!!
Good Luck Sweetie .. Please think about taking care of yourself .