Boyfriend Distancing himself?

Is it normal for men to pull- back a bit after spending a significant amount of time together? We spent 4 days and nights together last week and now he's being a little distant.
The topic of living together also came up and I think I offended him a little when I said the thought of living together scares me (we've been together 9 months and I love him so much but I can't imagine giving up my space). 
Please help! Also let me know if I'm being crazy because that's also a possibility