AITA for threatening CPS on my ex best friend?

I (22F) moved in with my lifelong best friend (23F) to help each other because her boyfriend (33m) went to jail. The apartment is his. His disability money pays the rent, so we were just paying utilities. I fell 2 weeks behind on our “agreement” due to emergency car repairs (my transmission failed) but communicated the whole time and still paid what I could. She kept changing the terms so I was actually paying her $100 more than needed. Instead of communicating with me, she sent someone to the apartment to threaten me physically for $100 because her boyfriend ran out of commissary money. Meanwhile, I’d been babysitting her child while she partied, cleaned her filth, bought groceries, and basically carried her while she slept all day or left her baby around strange men. She was selling drugs from her apartment, taking her baby on drug runs, and participating in prostitution. I’ve stayed quiet to protect her, but with her boyfriend (recently jailed for violence) returning next week, I’m seriously considering contacting CPS. She is unemployed and spent over $4,000 on a vacation instead of necessities for her baby. Her response: “I just want to have fun”… I’ve documented drug use around the baby, neglect, and disturbing requests like asking to leave her toddler home alone while we “FaceTimed” her from the bar. I ended up staying home with the baby because I refused to do such an abhorrent thing… There’s so much more that’s gone on that I’ve been considering contacting cps for a while… I don’t know what to do.