What does this dream mean? It was very confusing!?

So I have a boyfriend of almost a year. Like 11 and something months. Anyways the other night I had a dream that I suddenly appeared at my friend's party that she was holding. Then this dude walked up to me and said "hey baby, I missed you." It was a random looking guy though. His looks didn't even symbolize anyone I know in real life. Then I said "wait, who are you?" And he went, "I'm your boyfriend ____ of 11 months." His name wasn't my real life boyfriend's name. And I was like "you're not my boyfriend! You don't look like him, you don't sound like him, you even have a diff name!" Then he said "Well, we've been together almost a year." Then I ran off and spotted my mom (who's met my real boyfriend a LOT. I asked her where he was and said his name. Then she's like, who's he? I freaked out, so next I went over to my boyfriend's best friend's house and asked the same thing, "where's _____?" Then his friend goes, "who's he? I don't know anyone with that name." Then I realize my real boyfriend doesn't exist and I'm stuck with this fake boyfriend who says he's been dating me for the same amount of time. What does this mean?