As Romeo gazes at Juliet, Tyablt, and Paris, he realizes that the whole thing has come unraveled. He thinks that all is lost, and he despairs and reflects on the way things turned out.
As he sees Paris, he thinks about how he was going to marry Juliet. In Act V, Scene III everything seems unreal to him.
He told me Paris should have married Juliet.
Said he not so? or did I dream it so? (enotes etext p. 108)
Romeo comments that at least Paris gets to be buried with Juliet.
I'll bury thee in a triumphant grave.
A grave? O, no, a lantern, slaughtr'd youth,
For here lies Juliet, and her beauty makes(85)
This vault a feasting presence full of light.
Death, lie thou there, by a dead man interr'd (p. 108)
He asks Tybalt to forgive him, and calls him cousin.
Tybalt, liest thou there in thy bloody sheet?
O, what more favour can I do to thee
Than with that hand that cut thy youth in twain
To sunder his that was thine enemy? (p. 109)
Romeo personally did not feel any enmity toward Tybalt. It was the feuding families that put him in this situation. In the end, Romeo feels that as long as Juliet is dead there is no reason for him to live. He does not realize she has faked her death.