Feeling sad or low is not depression unless it does not go off within two weeks. If it is reaching beyond two weeks roughly, that means, your irregular emotions, behaviour and feelings are taking you to a mental stage called depression. Here are few sign/symptoms considering two weeks time that you are in Depression:
1. If you are sleeping a lot or you are not sleeping properly, that means there is something bothering you and you do not want to accept that it is bothering. To avoid this condition of insomnia or extreme sleeping, you should work on the problem immediately.
2. An unexpected weight loss or weight gain is doubtful. Sometimes you might see that your weight is in alteration without any change in your lifestyle. Do not ignore that it is the weirdest symptom and result of depression.
3. Inescapable sadness is really a confused state of mind. One does not know how to escape this sadness because one does not know the reason for sadness. Feelings like those that I am worthless, nothing good is happening to me, I am useless etc are the boosters of this sadness.
4. Change in interests regularly and diminished interest in every activity drives you to loneliness where you think negative all the time. You feel that you are a failure. For every negative result, you blame yourself. This sign should be considered carefully because, with this diminished interest, a person lost confidence. A person without confidence is just a skeleton with flesh and blood.
5. There are some symptoms, which are actually connected to the psychology. Unintentional and purposeless actions like the slowing thought process, emotional reactions or movement, the difference in your regular handwriting, forgetting things completely etc are psychomotor symptoms of Depression.
6. Suicidal ideation is the most dangerous symptom of Depression. As I mentioned above, low confidence hurts deeply every second. It develops restlessness resulting in many negative thoughts. Life is not worth living, my presence does not make a difference, it is my fault etc are the thoughts rum through the brain and one plans to attempt suicide thinking that it will settle everything.
7. Tiredness, anxiety, pains, cramps, irritability etc does not leave you.With this physical sickness, one becomes intolerant towards everything and starts overreacting. It results in messing up with people and things ultimately. Behavioural issues take birth.
There are more symptoms but these are quick to be noticed. So if you notice any of these in your friends or yourself, for two weeks regularly that means you really need to consider it. One can try Yoga to be good or might visit a counsellor.