Hallow Dear, During early pregnancy, sometimes there is bleeding at or around the date of expected menses. This is referred to as implantation bleeding by some. There are no symptoms whatsoever of implantation bleeding except little bleeding. In fact the first cardinal symptom of the pregnancy is missing a period; however it is masked when there is implantation bleeding. All other cardinal symptoms of early pregnancy appear about 10 days later. They are: 1. Nausea & vomiting with pica 2. Frequent Urination 3. Breast symptoms like engorgement with tenderness, dark discolouration of nipples & areola with areolar widening, Montgomery s tubercles under the areola and secretions though the nipples. The symptoms you are having, particularly the breast symptoms, thicker mucous and the mood changes, etc are most likely due to the Depot injection you had. Progesterone in depot does cause such symptoms. For confirmation, you may perform pregnancy test on overnight morning first urine sample about a week after the spotting you had; earlier the test may report false negative result.. Alternatively, Beta hCG test on your blood will give you the diagnosis 10 days after the last unprotected intercourse. I hope this helps you. Dr. Nishikant Shrotri