This is one of the most common questions people ask themselves before deciding whether to seek help, and it is a reasonable one. Life is difficult. Not every difficult period is a mental health condition. But the question can also function as a reason to delay, and delay is one of the things that tends to make depression harder to shift.
There are some useful distinctions to make.
Depression responds to circumstances differently than grief or stress does
If you have had a bereavement, a relationship breakdown, a job loss, or another significant event, feeling low is a natural and appropriate response. This is not depression in the clinical sense. The difference lies in what the low mood is attached to and how it behaves over time.
With situational low mood, your emotional state tends to track the circumstances. When things go well, you feel a bit better. When you have good news, you can experience some pleasure, even briefly. The mood is responsive.
In depression, the low mood tends to become self-sustaining. Good things happen and do not lift you. Time passes without improvement. The mood is no longer tracking the circumstances; it has taken on a life of its own.
The NHS notes that the key marker is persistence: most guidance points to two weeks of low mood or loss of interest as the threshold at which the picture starts to look more like depression than situational distress.
The role of duration
How long has this been going on? If you have felt this way for more than two weeks, consistently, that matters. Not because two weeks is a magic number, but because it is the point at which the symptoms are unlikely to be simply resolving on their own.
The PHQ-9 screener asks you to reflect on the past two weeks specifically. It takes two minutes and will give you a score that places your experience on a clinical spectrum from minimal to severe depression.
You do not need to be certain to get help
One of the things that delays people from seeking support is the sense that they need to definitively know they are depressed before they are entitled to help. This is not how it works. You can try a structured programme for mild to moderate depression without having a formal diagnosis. If the programme helps, that is useful information. If it does not, that is also useful information.
Related articles that might help: is it depression or am I just lazy? and can stress cause depression?
What to do if you are not sure
Start with the PHQ-9. Read Mind’s overview of depression. If your score suggests mild to moderate depression, consider starting a structured programme.
Beside is a free five-week programme over WhatsApp, built on the WHO Step-by-Step evidence base. It exists for exactly the situation you are describing: someone who is not sure whether what they are experiencing is depression, but who has been feeling low for long enough that it is worth doing something about. No referral needed. No waiting list. Start here.