I would request to get pregnancy
test done again (please use strip from a standard company). If in doubt, you need to see your doctor and get blood testing done to rule out pregnancy. Sometimes, even local infection/urine infection may lead to the symptoms you are experiencing. You need to get checked over and prescribed antibiotics if there are any signs of infection.
I would request to use regular contraceptive
measures rather than using morning after pills so often. Your GP/Family physician will be able to explain in details about various methods availbale, their pros and cons and dispense it for you to use.