People living with your s.o. (unmarried), do you sometimes get fed up?

I've been together with my other half for 1,5 years and lived together for the last 3 months of it. Since I moved in in July, things were great during the summer. We had a healthy balance of shared adventures, lazy days and separate time with our families. We're both 21. Now, however, since our third year of uni started - I'm a music teacher, he's an engineer, we're both studying AND working - things have been going not so well. Our sleeping schedule isn't in sync, because he's the most productive studying at night, whereas I get everything done during the day. As a result, he feels guilty for every moment he isn't studying and also for not spending enough time with me. I used to have a late job, but in the new place the work hours are 8.30am-5am and on other days uni doesn't last longer than 6pm either. So I get home, sleepy, maybe read a book or do some assignments and then go to bed before midnight. However, this is when my lad's real work begins. And at 4am he'll accidentally wake me by climbing into bed to finally sleep. And in the morning I'll wake at 7am and he'll just sleep for a few more hours and basically our communication these days is very limited. We try to do something together one night a week, but the last two weeks he had to cancel the date nights because he felt guilty for the time he'd lose not studying. I was a bit hurt, but didn't want to upset him. However he did notice and now he thinks I'm sad and depressed every time he does something without me.