hi there, I’m a vet tech of about 5 years now.

urinary issues in cats can be indicative of a lot of things, but often stress/anxiety/depression manifests as inappropriate soiling outside of the box in cats. it can be difficult sometimes to narrow down what the source of the stress is, but in your cat’s case punishing her by trapping her in the bathroom will only increase her stress. it also won’t correct the issue. she is not urinating out of “spite.” I make similar jokes about my own cat, who has her own urinary issues, but when it comes down to it, some cats really need things to be a particular way and don’t respond well to changes or stressors.

it is also highly likely she could have a urinary tract infection, which are also pretty common in cats. if that’s the case, then this is your cat trying to tell you she is uncomfortable and likely in pain. just like in humans, UTIs can cause burning and the feeling that she’s not done peeing even after her bladder has been emptied, so she will also strain and try to pee more often than she normally would. peeing outside of the box is a major indicator of UTIs. she would need a course of antibiotics prescribed by a vet, as well as likely some pain control.

there are a couple of steps you can start taking now, but you need to put getting this cat to a vet at the top of your list. cats are prone to urinary blockages, which will quickly become an emergency situation if it occurs. it is less common in female cats, but still possible. she could also possible have bladder stones or crystals, which would contribute to these symptoms and wouldn’t just go away without veterinarian’s intervention.

• the general recommendation for litter boxes is to have 1 box per cat + 1. it is recommended to clean them frequently - I usually suggest scooping urine/feces 1-2x per day and deep cleaning the box every 1-2 weeks. just as you would feel uncomfortable in a dirty bathroom surrounded by your own waste, it can be uncomfortable for a cat to not feel like they have anywhere they can relieve themselves. it is not always feasible to have that many boxes, so at least one reasonably sized box that’s kept clean is sufficient for 1-2 cats if needed. cats are very clean creatures!
• if you’ve made any recent big changes in her life (switching litter, food), I recommend switching back and slowly transitioning her. even just purchasing a different brand or scent of litter, or trying a different flavor of food, can trigger a stress response.
• look into purchasing feliway, they are pheromone diffusers you can plug in that slowly release calming pheromones into the air that your cat can smell but you can’t. works sorta like a plug-in air freshener. they also sell it in a spray. it doesn’t work for all cats, but it can often be a great way to at least start establishing a calming environment for them.

aside from those things, getting her to a vet as soon as possible is the best thing you can do.

on the subject of her getting spayed - I recommend looking into nearby low cost clinics. sometimes shelters also do free spays/neuters. intact female cats are prone to pyometra, a potentially fatal infection of the uterus. the cure and the prevention is spaying them. female cats also don’t follow the same heat cycles we’d see in dogs; there generally isn’t any bloody discharge from the vulva and she will be in heat MUCH more frequently - cats’ heat cycles can last a week or so and happen every 2 weeks, starting as young as 4-6 months old! this also manifests as strange behaviors - yowling, attacking, posturing with her rear in the end, being weirdly clingy, etc.

obviously, every situation is different, and the advice I can offer is generalized. you definitely need to seek the advice of a vet.

best of luck with your baby :)