I have to use the bathroom all the time and im only 18?

I seriously think i have something wrong . When im laying in bed i get the urge to use the restroom every 5-10 minutes even if i have not drank anything for hours . Its really scaring me because this is what my grandfather does and he has prostate cancer . I cant see a doctor right now because i have no insurence and dont have the money to pay for it but i want to know if you think this is serious at all . This has been happening to me for about 5 months strait . At first i thought it would go away but it doest and it effects everything i do . Please help!!!