Why was Equiano in despair in the West Indies?

I believe that Equiano was in despair at the thought of the voyage..... not so much the West Indies.

Thus, at the moment I expected all my toils to end, was I plunged, as I supposed, in a new slavery; in comparison of which all my service hitherto had been 'perfect freedom;' and whose horrors, always present to my mind, now rushed on it with tenfold aggravation. I wept very bitterly for some time: and began to think that I must have done something to displease the Lord, that he thus punished me so severely.