1/3 of all pregnancies end in natural miscarriage. In order to confirm a pregnancy, you will need an ultrasound. This will also determine how far along the pregnancy may be.
Many of your pregnancy options depend on exactly how far along you are. It is usually not possible to confirm pregnancy before 5 weeks past your last menstrual period, so you will need to have another ultrasound done in about a week. Waiting another week will NOT limit your ability to have an abortion.