Her own collection wouldnt be valid without chain of custody but would give her an answer.
Best to have a urine and blood to done before 12 hours to get an answer, mention possible research chem as they'll investigate further.
Best thing to do is make a plan of getting yourself as uickly as possible after an event that you're questioning to a hospital so they can do the investigation.
Just be aware, pressing charges doesn't happen just like that. If you just want to know if you've been drugged with anything besides weed, get a scraping of the bong or any leftover baggies, your own urine and go to a hospital. The hospitals have to report assaults to police and up to OP what she does there, tell the whole story which could then automatically start an investigation or not say anything until you're ready.
Sounds like some kind of flakka tbh.
The cops decide if charges are going to be laid after doing an investigation, even if she doesn't want to press charges later. This is why people change their minds after the fact, its the only way to get charges dropped.
So OP, the dude sounds like a tool, maybe you need intervention to leave so up to you if you really want to know or not.
If you don't want to lose him, for whatever reason, and just want to know wtf is going on, set up a camera of sorts?