I recently read on a favorite website (www.helpguide.org) that different forms of abuse can cause depression/anxiety (see Psychological Warning Signs bottom of article). I realized that sometimes we don't even recognize or fully understand the source of our depression. Another article asserted that several medical issues like an under/overactive thyroid or anemia can cause symptoms that mimic depression. The article suggested starting with a visit to your general doctor to rule out any of these causes first.
If you have already done tests to rule out a medical condition and are not sure what to do next, the following article Understanding Depression can help by educating on the different types of depression, causes of, and potential paths to healing. Seeking help from a professional might be an answer.
No one is going to care more about you than YOU! Make an appointment with your doctor if you need to; find out what options are available for you to help you recover. Depression can make everything feel overwhelming, so start small by doing just one thing a day to get you on a path to healing.