Was my drink spiked or was it just the alcohol?

I was sexually assaulted by a friend after a few drinks. The thing is, it was only after 2 rum and cokes that I felt drunk, so drunk that I couldn't walk on my own, I was dizzy, and I felt really sleepy. The first rum and coke I drank completely, watched it get poured. The second I left downstairs when I went to the bathroom. I was wondering if those are symptoms of something other than alcohol. While I am young and not an experienced drinker, I have never felt this way before when drunk, even after shots and lots of beers.