All of us develop certain strengths and some limitations in the way we cope with things in life. It's our vulnerabilities that get exposed during any stresses, major or minor, leading to certain dysfunctions like mood fluctuations, not being able to enjoy, losing interest or motivation, lethargy and sometimes negative ruminations, sleep and appetite disturbance etc. This does not necessarily mean that you are severely depressed and you need treatment. Most minor mood fluctuations can be dealt with consistent practice of certain techniques and lifestyle modifications
Next Steps
Start looking at these experiences as objectively as possible in the context of your personality, life circumstances, support network and whatever may have triggered it in the recent past. Get present to these emotions, let them be, and carry on focusing on your daily routine and futuristic actions irrespective of how you feel. Take practical measures to whatever is not working. Enjoy whatever is working. Don't fight with your emotions. Focus on good lifestyle practices.
Health Tips
Only if things get more difficult and start to affect you significantly, then you will need professional help to treat possible underlying depression after a comprehensive assessment. Depression is a treatable condition usually with psychological therapy and medicines if necessary. Best wishes