Answer:
I believe, put simply, Frankenstein has been killed by his monster. His friend, whose name cannot be derived from the passage, has found Frankenstein's corpse and Frankenstein's monster above him. Frankenstein's monster seems remorseful about killing their creator. However, the 'friend' is basically saying 'Bro, if you had just listened to your gut and your conscience, my dude, Frankenstein would still be alive'. What happened after is a bit murky, but basically, Frankenstein's monster is like,
'Do you dream? Do you think I don't feel hurt and guilt? After the murder of Clerval, I went off to Switzerland, feeling down. I felt bad for Frankenstein, then it turned to horror. I felt disgusted about myself. But then I found out that Frankenstein, the guy who made me and all of my problems, wanted to be happy. While he made my life horrible and piled torments on me, he tried to find happiness in the things I couldn't experience. Then I became angry, and I wanted revenge. I put aside my problems and adapted to the way I had chosen to feel...'
This is still a bit off, and it might not solve the entire problem, but I hope it clears up a few things??