Hi,
Depression is a very strong word. There might be chances that you might be feeling low due to the current situation of covid all across. Certain times it is just that certain hormones like dopamine and serotonin fluctuates (reasons might be due to menstrual cycle, age, current situation in life,etc)
One should not be in a hurry to get conclusive about the diagnosis rather what symptoms you are having if you could explain in detail that might be helpful
Next Steps
Observe carefully why are you having such mental changes since 2-3 weeks. Consult a good doctor who understands the problem properly
Health Tips
Try to talk to people about your situation. Do not be alone in such situation
Feel free to consult
Take care