I’ve never felt like I was truly happy

I went through my whole life thinking that happiness was just a myth. It just seems like it’s an idea society gave us to make us want to live, to make us want to reproduce. I feel like it’s just a concept to keep us all trying and working as a human race. I feel like I’ve never been truly happy since I was a child. It’s always just a sad unhappy feeling. Nothing makes me truly happy! Why am I even here then? Why do humans exist!?