Hi Agustin. In this case, "awkwardly" does mean embarrassed or slightly unsure of oneself. Perhaps Robin isn't sure how his/her offer to help will be received or perceived. In any case, the use of the word "awkwardly" indicates uncertainty.

I agree with Andrew that it implies uncertainty. He’s feeling awkward, uncomfortable and unsure of what to do. I would interpret it like Robin is seeing someone carry something heavy and wants to help (or thinks he should help)... but isn’t sure how to help, or if he can help. So he feels awkward and unclear about how to handle the situation.