I'm kind of in the same boat. I haven't worked in over 10 years, but my disability benefits were taken away. I've applied for reconsideration and then appealed when that was denied because I can keep the benefits going while I wait for that to play out.
My current plan is to get a shit job just to have something to put on a resume. Places like fast food and convenience stores will hire anyone who has a pulse and can make change. Maybe you can try something like that? I'm trying to stay positive about it by telling myself it'll be temporary.
If the buildings vent stack is operating properly smells shouldn't be coming out of the drains, no matter how much they pour down it.
If the vent stack is clogged or insufficiently sized, air could be forced up through the traps, but you'd be smelling sewer gas too. It's a really rank smell you'd notice, so I think the polysytrene smell is probably coming in some other way.