Why isn't he coming online anymore?

i have been talking to my crush online for quite some time. But he hasnt been coming online AT ALL recently. He has exams at the moment, which is quite understandable, but is it normal that he doens't come online at all? i mean, surely, if he liked me, he would take the time to sign in in between his revison breaks right?..im scared he wont ever come online after this and that he may have gotten over me or smth? what do i do? i have been waiting and have decided to not commmunicate to him till his exams finish