Welcome! As Leeshor said, it appears to be functioning normally. RAM is Random Access Memory. The system loads info into it for quick access, reducing load times. The system also automatically moves info out of RAM as needed to free up space. As long as there's SOME left, it's safe to assume the system is doing what it was designed to do. Clearing EVERYTHING out of RAM will only frustrate you more, because it will take longer to load certain applications.
It helps to think of RAM like a desk. You put the papers you're working on on your desk. You may have Facebook papers on top because that's what you're currently using, but that doesn't mean that you take the Instagram and Twitter papers off your desk just to use the Facebook papers. You leave them in the pile of papers so you can refer back to them quickly. Now, when your desk gets full and you haven't used the Instagram papers in a quite a while, you might take them off of the desk to make room for your Angry Birds papers. This is basically what the Android OS does with data in RAM. Hope that helps to clarify, rather than being more confusing.