Could my drink have been spiked?

I was out last night and had had quite a lot to drink before we went to the club but as soon as I got to the club I bought my last drink for the night. I remember everything up to and just after buying the drink but nothing (and I mean absolutely nothing, my friends have been telling me so much that I have no recollection of) until we left 2 or 3 hours later. I've never forgotten a whole night before so was wondering if my drink could have been spiked or if it was just down to the alcohol. Also this may sound silly but I've never had a sound nights sleep after a night out, I always wake up every few hours but I slept like a log for 9 hours which never happens to me after alcohol.I've also drank much more than I had last night and remembered more of the nights which seems strange. But then again if I was spiked then surely the effects wouldn't have worn off by the time I got home so maybe it was just the alcohol. As you can see I'm a bit confused so any help would be much appreciated!