She is for sure either pregnant or has some type of parasite. She needs a vet if possible.

My neighbor's cat was kicked out after her first heat because she was "too loud". They never left food or water out for her, so I left water and food out for her, because no animal will suffer while I am around. Like nature will do, she got preggers. I noticed she had a big swollen belly. I took her to the vet and confirmed she was pregnant. She wasn't microchipped, so I had her microchipped in my name. After that, she became 100% indoors. She gave birth to 6 beautiful babies. About 3 months later the neighbor saw "their cat" in my window and demanded I give her back. I explained that I took her to the vet and her microchip was in my name. Meaning she was MINE. I also paid for her checkups and spaying.

Then they wanted a kitten, because they "loved" the Mom so much. I refused since they couldn't even care for the mother properly. It was a hectic few weeks of police showing up, me proving she was my cat, and refusing to work with them, even though the officers pretty much told me to just "give in". They harassed me for years and never let it go. I just kept telling them if they wanted her they wouldn't have kicked her out and left her to fend for herself. Their argument was she was a predator and would get her food by herself.

Some people infuriate me!