I'm not bilingual

I thought I knew spanish pretty well, or at least well enough to be able to listen to a real-life conversation in spanish and be able to tell, for the most part, what was being said, but I was very wrong. I started a new job about a week ago, and there were two guys in my orientation class that knew perfect english but were bilingual, and I was talking to one of them. I told him I kind of knew spanish so he said something to me and I just stared at him. I told him to say that a LOT slower and I would probably know, mostly, what he was saying. I mean, I knew spanish was spoken fast but wow. Apparently I'm not as good as I thought I was, I need to learn to listen faster. Anyway, I still am trying to learn spanish even though it's getting harder the further I get into it.