Is there really an afterlife?

Yes.  While we cannot fully explain life after death, it is there.  When God created the human race He gave us all a soul (Genesis 2:7).  Throughout the Bible we read that the soul is everlasting, meaning that it never dies even though our physical bodies do.  For those who accept Jesus as their Lord and Savior we shall enter into Heaven, which is described in Revelation 21.  For those who refuse Jesus they will go to Hell and then the Lake of Fire (Revelation 20:11-15).  Our souls will live forever but it is up to us to decide where we will live, Heaven or Hell.