Things could feel a bit strained now. The two of you seem to be working at cross-purposes; your schedules are off, you're both a little moody, and your libidos might not be up to par. You might have lingering doubts at the back of your mind about the relationship -- is this really living up to everything you wanted it to be?
Is it even what you thought it would be? Dissatisfaction and anxiety reign now. It's easy to press each other's buttons, and you know each other well enough to know just which ones to push! So don't do it. Keep a handle on yourself; stay calm even when things get tense. The best thing to do during a period like this is just hunker down and wait it out. If you can, spend a little time apart -- absence, as they say, makes the heart grow fonder. If you do have to spend a lot of time in close quarters, don't be surprised if arguments break out and feelings get a little hurt. If this happens, think of it as an emotional clearing of the air for your relationship -- an important thing to do every now and then, even if it's not a fun one. In a week or two, things will start to look rosy again, and you won't even remember what you were so upset about.