New languages aren't all equal. As you are a native English speaker, languages such as French and Spanish will be naturally easier for you to learn as they are structurally and historically similar and familiar languages. There are also great differences in culture, which naturally becomes ingrained into languages. Korean is not similar to English at all, so you have to think in a very different way to begin to understand and follow it naturally. You may be used to moving through material and understanding things quickly with other languages because they are more natural to you, so it's best not to try to compare it to those in such a way or you may be discouraged. Keep studying. When you become familiar with vocabulary, try not to translate it in your head. A key part of learning such a different language is learning to think in an entirely different way. Once you can do this, you will find that it gets easier.

I would like to say to you "don't worry about that and just take it the way it really is" because even Asians in the similar circle of the culture feel difficult to learn another Asian language. However it would be very helpful, I bet, to understand and learn our culture before starting to learn the language.