Am I depressed? Or am I just sad?

First, of all, I want you to listen very closely to what I have to say, these types of things can be extremely serious, but they shouldn't have to be. What you're feeling is normal for a 15 year old, you are young and confused. I was in your position when I was your age, worse actually, I actually attempted suicide. Don't let it get that bad, because it will get better. It always does. Think of it like this, most of us can live long lives. With all the time, it will get better, IT WILL. No matter what, it always does. You see, once you start growing, and start understanding, the feeling will slowly vanish. Pretty soon you have almost forgotten that you were like this in the first place. Sure it sucks right now, but I assure you 100% that it will go away. I put that on my life, I promise. It might get worse, sure. But it will get better. You were happy once right? Who says you can't be happy again? It wont be like that forever. This is something, again, I can assure. Just keep pushing forward. And to answer your question, no you're probably not depressed, I mean you are, but it's more of a normal depression that happens to everyone. Just keep going. You'll do fine. I hope this helped in some way.

if you are having suicidal thoughts than you are not just sad, it sounds like you have chronic depression. but if you felt better with antidepressants than that is good because it can be controlled. go back to your doctor, tell your parents whats going on. I have been there, and so just know that where you are concerned there is hope because it seems like the meds worked before. until then know that nothing is your fault, and that you are not defined by your depression. its hard, but hang in there, its worth it!