How do you know if your boyfriend is not into you anymore?

Dating 2+ years, now he's busy w/work (works 7-midnight) His roommate moved out w/o any warning so he has to take over the lease or find a new roommate.

He has been so stressed but I'm not sure if its stress or he just love me anymore because he hasn't called me in 2 days and we used to talk every single day. And he is an outgoing person, its not like he's a shy person.