Mixed Signals

My bf and I first got together in June. He was great! Was easy to talk to, wanted to hang out a lot, and made an effort in the relationship. Now, after 3 months I feel like something seems off. Understandably he balances work and school and his family. I totally get that. But when we do hang out he seems bored the whole time, doesn't want to stay to long, or tries to have sex. That's if he even comes over. Towards the beginning of August I noticed he is inconsistent with our plans (never used to be), doesn't respond to my texts for hours but can go on fb the whole time. I feel like he's becoming distant and idk what to do. I try giving him space and I try to show him I'm giving effort but regardless what I do he still acts the same. I'm so confused, any advice?