I live in a really big house full of young people, I'm scared and don't know how to handle this safely

I live in a duplex house with friends with 13 people total, one roommate has his very pregnant girlfriend staying with us right now too. We've all been off work and staying home for 2-3 weeks now and I have not been displaying symptoms nor has anyone else here as far as I know. I have been bouncing back in between my house and my girlfriend's ( I know many people would question why I'd allow contact with her right now, but she's the closest thing to family I have, she is essentially) a few minutes away but not going out unless necessary other than that.

Quarantine with a bunch of young people who are friends is weird. We're not supposed to have gatherings or seeing other people in general, but I think it's likely that if anyone in my home has the virus, we've all been exposed at this point, as well as my girlfriend. So people have been lax about hanging out with each other within my house? We've mostly been keeping to ourselves anyways but tonight for example we had a "house prom" and just had everyone in the house dressed up and was hanging out in our front lawn. None of this was my idea, it feels like maybe we're not taking it seriously enough, but I also can't really control 13 people especially if this is going to be a multiple month situation which is looking more and more likely.

I tried hunkering down with my girlfriend at her place but I was worried that her roommates didn't want me to stick around for too long so I feel like I have to spend time both here and there. Which makes me nervous and her nervous.

I started getting slight nose blockages and coughing along with body ache today and I'm sitting here at 3 am worried about having the virus but also feeling exasperated because there seems to be no good solution to keeping safe in our current living situations..