What does it mean if you pee blood and it hurts really bad but your not on your period?

Cystitis. Urinary infection in your bladder. You need to be on antibiotics. Good luck.
UTI. It means you have a urinary tract infection. You should see a doctor as soon as you can so that he/she can get a urine sample to send for a culture and get you started on an antibiotic.
Likely a UTI. The 3 major considerations if the onset of the symptoms occured acutely is that of a urinary tract infection, urethritis from a STI or nephrolithiaisis. (kidney stones) i recommend contacting your docotor as diagnostic testing can differentiate the above and then you can receive appropriate treatment.