Explain the death of Kat. How does Paul react?

From the text:

The anguish of solitude rises up in me. When Kat is taken away I will not have one friend left.

Do I walk? Have I feet still? I raise my eyes, I let them move round, and turn myself with them, one circle, one circle, and I stand in the midst. All is as usual. Only the Militiaman Stanislaus Katczinsky has died.

Paul is numb when he realizes he's lost his friend...... then he's lost. Did he pass out..... or just stop feeling completely? We are not told.