Friend passed out what happened?

So me and my friend went to a party the other night everything went fine. She got drunk, but nothing new. The next day we go over to my other friends house and smoke a few bowls. Again nothing special. All of the sudden she just falls straight to the ground and hits her head on a cabinet. I had no idea what was going on and she barely reacted to hitting her head and just laid there. i knew something was up so i helped her up and asked what wrongs and she barely responded, then she slowly hunches over and falls backwards and passes out again! So now I'm freaking out, I slap her face a little to wake her up and i pull her up to go sit her on the couch. On the way to the couch she can barely take 5 steps without her whole body shutting down and not being responsive. She'd just slump to the ground. Every time its only for about 20 sec then she can barely respond. I'd have to yell her name for her to wake back up. She'll open her eyes, stand back up and say im fine then the next 5 steps she would just go limp again. i had to hold her up the entire time so that when she blacked out she wouldn't fall and hit something. Then i finally sat her down cuz she could not walk without passing out. She was in a cold sweat and said she just wanted to sleep but i wouldn't let her afraid she wouldn't wake back up. After a while she was fine and was light headed the rest of the day. So my question is what happened!? Did she get drugged at the party? She does not do any other drugs besides pot and alcohol and she was not dehydrated and had plenty of sleep.