The symptoms that you have mentioned, seem to be indicative of Bereavement more than Depression. The intensity of the Bereavement / Grief is dependent on the time lapse after your Mother's sad demise and the increase or decrease in your symptoms.
Normally a person is able to cope up with the loss over 6 months.
Persistent Complex Bereavement disorder is a condition where a person experiences prolonged grief over death of a near and dear one.
Next Steps
It is advisable to visit a clinical psychologist for detailed assessment and further guidance.
Health Tips
Walk or any physical activity for 45 - 60 minutes daily.