Struggling with POTS episodes and unsupportive family

I was able to get a diagnosis 7 months after noticing symptoms. I have a cardiologist appointment in a few weeks but is there anything I can do to help POTS episodes? They just keep getting worse and it’s a struggle to even sit down -I get extremely dizzy just by doing that I don’t know what to do. I have to lay down all the time these days it’s so annoying. My dad just thinks I’m being super lazy all the time and he puts me down by telling me it’s all in my head. I know my body. If I could stand for a minute without getting dizzy, I would. But I can’t.