Nauseating smell in my house! electrians, pest people, etc please read and help?

There is this smell in my house that comes and goes I have never smelled anything so disgusting and literally just threw up from it. It happened about 2 months ago and then again yesterday and right now. It seems to start in my living room then will infiltrate my kitchen and I have to close my bedroom door to keep it from spreading in here. It almost smells like water and maybe fish but it has like this toxic smell like whatever it is its bad. Someone mentioned it might be a cats urine or a mouses urine but I don't have a cat and I have yet to see any mice. I don't think mouse urine would smell this...toxic? The only thing I can think of is that it might have something to do with the heater or electricity. I haven't seen mice in my apartment but I do hear some sort of rodents like squirrels running through the walls at night sometimes. Is it possible that they could have chewed something up in there and that's what's causing the smell? I'm disgusted. I'm going to go throw up again for relief. :/