“I think I have depression?”

I doubt you have depression. It is more likely that you are experiencing a temporary low mood. Depression is defined as a condition that includes depressed mood, almost no interest in activities, significant weight loss or gain, poor sleep, no energy and that these symptoms are present continuously for at least 2 weeks. You say you are bummed out for no reason. In my experience, when we look carefully, we always do find a reason it just might not be obvious at first glance.

It may be or depression or it may be due to the times. You should speak to your parents so they can help you.

Thank you for the question and I commend you for taking charge of your life by recognizing the early symptoms of and an illness that could become chronic if not recognized and treated earlier. Also, I am sorry that you are feeling this way at this tender young age. Now to your question: From the description of your condition, it doesn’t seem like Major Clinical Depression.
One should have at least 5 or more of the following symptoms for the same two weeks period and represent a change from the previous functioning:

1. Depressed mood most of the day early every day like feeling sad, empty, hopeless.

2. Markedly diminished interest or pleasure in all or almost all activities most of the day, nearly every day.

3. Decrease or increase in appetite nearly every day or significant weight loss

4. Insomnia or hypersomnia nearly everyday

5. Being restless or being slowed down compared to previously

6. Fatigue or loss of energy nearly everyday

7. Feeling of worthlessness or excessive or inappropriate guilt nearly everyday

8. Diminished ability to think or concentrate , or indecisiveness nearly everyday.

9. Thoughts of death or suicidal ideation.

Even though you probably would not meet this criteria, my advice would be to seek out some counseling/therapy to mitigate the risk of developing full major depressive illness.
Hope it will help.

You might you certainly need psychotherapy.

I would need to know more about you to be able to answer your question in a useful way. Was there anything hurtful or unpleasant happening in your family: parents or older siblings criticizing you harshly? Sickness or a death in the family? Not doing well at school? If none of those troublesome things were happening, then I would think whether at 12 you were having your first period? Quite a percentage of girls begin to have symptoms of depression and/or irritability - as they begin their menstrual life - even if everything else is OK in their family life, friendships, etc. If your depression turns out to be "hormonal" (because of the menstrual-induced changes), there are medicines that can lessen the depression. If your depression seems to have nothing to do with your period, then I'd want to know 2 things: are there other family members (parents, aunts & uncles, cousins, grandparents) who suffer from depression? And: are there any of those things I mentioned about family life, friends, school problems affecting you in a negative way that could trigger a depressed mood.

Dr. Stone

To have depression, symptoms have to persist for over 2 weeks.