Blood tinged urine.

Dr. Marie,

My cat does not pee in her litterbox. Instead she will pee right outside the box, and even on my parents bed! After doing some research, we thought she may be stressed out because I was gone on a vacation for a week. We thought the description fit perfectly because the article said stress in a cat can cause red tinged urine, which is also something i have noticed. So after i got back from my trip I made sure to give her extra attention, and since then I havn't noticed anymore red urine.
Yet, she still continues to pee anywhere but in the box. After doing more research I thought she may be associating unpleasant feelings with her current box. So i purchased her a brand new box, and new litter. She still pees in random places. We have had to throw out a couple pillows a blanket, and she has peed on my parents matress so many times we have to throw that out as well. Obviously this has become a problem.
I love my cat so much and will do anything to help her. Any suggestion or answer you can provide me with is greatly appriciated.
ThankYou, Alexis