I'd Moby-Dick a hard/daunting read or am I just stupid?

I'm listening to Moby-Dick on audiobook and I feel like I may have bitten off more than I can chew with it (I'm at the part where Ishmael got kicked by Ahab's fake leg, and just finished his detailed analyses of different whale breeds, chapter 30-something and about 6-7 hours into the audiobook)

Point is, I can only understand about half of what's going on, a general idea and hardly anything else, I feel like a lot of it is just flying over my head, and I may be out of my depth with this one. Am I the only one who's having/has had this issue, and what should I do about it? I don't want to ditch the audiobook, since I've already put so much time listening to it, but I'm only 1/4 of the way in, and I feel like I'm in over my head, so what would you guys say about this, and what advice would you have for me as to what I should do next?