My cat's stomach is bloated and she's struggling to pee. What's wrong?

I'm sorry to hear Rusty is having problems urinating. She could have a urinary tract infection, urinary crystals, or potentially cystitis, which is inflammation of the bladder. I would also be concerned about gas and/or constipation as this can make a cat's abdomen look distended. I would recommend you take Rusty in for an exam with your veterinarian. She likely needs to have her urine checked and her abdomen palpated. Normally we can feel most of the organs in a cat's abdomen. After a good physical exam and abdominal palpation, your vet should be able to have a better idea as to what is going on with her abdomen and how to proceed. Sometimes we need to use further imaging, like x-rays or ultrasound if we can't feel what is going on. My hope is that it's a simple infection that can be treated with some antibiotics. Good luck!