I have been on Depo for over 18 months, never missed or been late on a dose. I have not had a period since May, but tested negative for pregnancy at my last dose in August. For the last week I have had very tender, swollen breasts, fatigue, headache, diarrhea and nausea. I have two children and recognize pregnancy but am hesitant to believe I may be considering my religious use of Depo. Could it be possible or is something else at the cause?