Why does this happen?

Does anyone else feel happy for awhile but then as soon as one small bad thing happens you fall back into depression? And like 10x worse than before? It’s like a cycle and I hate it. I’m so sad lately and I’ve relapsed sh and I honestly hate life and I’m so angry and my step mum and dad because they won’t help me, and my dad just makes me wanna kms. And I know that they know I’m bad again. So why won’t they ask if I’m okay? I’m so sick of everything. Is something wrong with me?