ELDERLY CAT HELP ☹

Lauren • You get what you give.
My 18/19 year old cat has been peeing everywhere. We keep her litter clean. It's the same litter she's used for at least the past 10 years. We haven't changed anything. She is confined to my room because I currently live with my in laws and their dog isn't cat friendly. That's not an issue, the cat usually is fine hanging out in the room, lounging in the window, etc.
I'm pregnant and can't be dealing with a room filled with cat pee and ammonia. I'm worried about toxoplasma first off and the ammonia as well. Plus the stress of the situation. I tried crating her at night and she meows and whines, keeping me up. Another problem when you're pregnant. It's already hard enough to sleep! 
I'm so frustrated and can't seem to solve her behavior issues. It's a huge stressor for me and at the age of 19, I can't regime her. It's driving me insane. What should I do?