It's the first one. Simply put, the second one doesn't make any sense. I can't come up with any kind of reasonable explanation for why something would be written that way, nor have I ever seen the stem of
いただける used as a noun.
Frankly only after reading this question did I even realize that there were dictionary entries for
いただける specifically, since it comes from the potential form of
The first one, on the other hand, pretty clearly means something like
Maybe (I) was just trying to believe it
Though the topic is omitted and could consequently could be anyone, obviously including people other than the speaker. I just default to