Weird Smell in Mobile Home?

It's not something I can identify. It is nothing I've ever smelled before. I live in a single wide trailer, you know, the generic, run of the mill kind, they used to make back in the day. The kind with ugly brown shutters. I keep getting this odd smell that isn't something dead or rotten. It doesn't smell like must or mold. It doesn't smell like gas or a chemical. I don't know what it is. I'm not even sure how to describe it. It reminds me of microwaved chicken nuggets that aren't quite right. It has a sour quality to it, and perhaps a hint of bad breath. Weird, I know. It doesn't smell bad per say, more that I just can't stand the smell. My husband doesn't seem to notice. The trailer we rented before this one was a few lots down in the same trailer park and I smelled it there too. I notice it indoors more than outdoors. I thought maybe it was the soil (we have a natural spring that runs under the yards) or something in the walls. I feel like I'm going crazy and I don't know what it is, where it's coming from, what to do about it, or if I'm even really smelling it (I am.) Before we moved into this trailer park I never smelled anything similar before. Does anyone have any ideas or suggestions?