Welcome to the forums and thanks for joining us. I'm glad that you're here.
I'm sorry to hear about what's happened with your ex - I think breakups are hard on their own, let alone being friends. It seems like the breakup was a bit of a messy one, and I'm glad that you know that you're nobodies reason for unhappiness -what a cruel thing to say.
With your question though, that one is a little more complex.
Often, with the symptoms of depression (that you've probably read online), it can seemingly come about with a life event - like in breakups for example, or grief. As an example, if someone lost a loved one, they might be really sad and they might even meet the criteria for depression - but that doesn't mean they'll get a diagnosis. For a diagnosis, it's having met all this criteria/symptoms for a while now (like a long time after grief or a breakup).
At the same time though, a diagnosis or quiz doesn't really matter - what matters is how you're feeling. I know that whether it's a 'diagnosis' or 'hormonal emotions' doesn't matter to me. Both of them are very real. Both of them suck. Both of them are valid, and both of them are worthy of getting some help.
Would you be open to having a chat with someone you trust about it? Whether it's your parents, GP or school counsellor?