Birthday = No Present from BF?

Hey ladies...so I turn 21 this Saturday (woo!) and I'm leaving tomorrow (Friday night) for a weekend in Vegas (double woo!). It's going to be a girl's weekend so tonight was the last night I saw my boyfriend until I get back next week. We hung out, watched tv and ordered some food and I was waiting for him to bring out a little gift or something but the end of the night came and he said he had to go to bed for work in the morning. A little backstory, we've been dating for 5 months and have been "official" for about 2 1/2. He is also fully aware that Saturday is a milestone birthday for me. Am I justified in being a little upset that he didn't even get me a card?