Why is it that every time I get up, I feel dizzy?

So this has been happening for as long as I can remember. When I get out of bed in the morning I get dizzy and my vision goes black for a few seconds and I have to sit down. Usually if I look at the light my vision comes back quicker. Now it’s happening more often, like when I get up off a chair or the couch. I don’t know if this is normal or what, but I need help. Please don’t tell me to go to the doctor cause my parents won’t take me. They are the kind who only takes you to the doctor if your leg has been cut off or something. Also we won’t be able to afford it seeing as how my dad just had a heart attack and we are spending the last of our money on medical stuff for him.