<human>: Can you condense the text into three sentences or less?

The other day my girlfriend and i of 3 years (known each other for 9) went to a mutual friend's house to play some board games and have a few drinks. A friend of my friends went into his room and did cocaine. After my girlfriend went to the washroom she went straight into the guy's room. I caught her with a straw in her hand, but didn't snort any. I was pissed for the night and she promised not to do it at all. 2:30am rolls around and I decided to go home. She wanted to stay. the homeowner promised she would get home safe. So i went home. She didn't arrive home till 5am.  She assures me she fell asleep and no one woke her up. and she took a cab home.
<bot>: what should i think? I've lost people to drugs before and its making me physically sick thinking about my girlfriend doing coke. Advice?