[Lizzie]

If you took an emergency contraceptive I would not worry about the possibility of being pregnant. They are extremely effective and only fail in very rare cases. That combined with the fact that you did get your period and two negative tests leads me to believe that this pain is caused by something else.

The weird cycle you experienced was most likely a side effect of the emergency contraception that you took. The morning after pill is known to cause periods to become irregular.

Are you sure the pain is isolated to under your left ribs? Nauseous and strong abdominal pain could be a sign of appendicitis. If the pain continues, or you start vomiting I would highly suggest you seek medical attention.