So... He needs space?

Alright so here it goes. Me and my boyfriend have been doing great lately. We usually only hang out once per week due to busy work schedules but we had the opportunity to hang out more this week. Him and I are about to go off to separate colleges in a month but have agreed to stay together. So moving on to what happened yesterday... We were going to hang out Saturday but then his grandma had to have cancerous tissues removed. I have told him I am here for him if he ever needs to talk. So I asked if we could still see each other on Saturday and he said "Maybe" to everything I suggested. I was starting to get very annoyed because I didn't get what the holdup was. I always want to see him and I feel like I am the one always initiating things. So I asked him if he needed space or something and he goes "Maybe a lil bit." I don't know what to do. We don't see each other that often and we honestly don't text that often either because he's too busy playing video games. I am at a loss ladies. What does that even mean? I even asked him "So what does that mean then?" And he goes "You're fine babe." What the hell. He's with his friends camping now so I can't clarify what the hell is going on. I love him to death and I would do anything for him but I am not going to be in a relationship where I feel annoying or like a pest when I simply want to hang out. What does all this mean ladies? 
Side note: He's the one assuring me we will make it through college and he just "knows" we will end up together and he wants to marry me... He even bought me a promise ring. 
*The reason I'm adding anonymously is because my boyfriend is on here*