Thanks for the query.
There should be at-least two months gap between the emergency pills.
So as you maintained the sufficient gap the symptoms you had may not be due repeat use of the pill.
Anyhow sometimes emergency pill can cause side effects like bloating
sensation of the abdomen, nausea
So you better go for depo as you decided. Meanwhile you can take symptomatic treatment.
For more details you can ask me through: http://www.healthcaremagic.com/doctors/dr-sree-gouri-sr/63429