What do the meanings have in common?
Moreover, I read several tarot books during the last year, so I saw different interpretations. What should I do now? Just sticking to what make sens to me??
What you should do is remember that you're not going to be reading this card alone, by itself, with no idea of what it might be referring to. When you lay down that card, it will be in answer to a question, asked by someone and in a position in your spread. It's rather like seeing a word in a sentence. See that word by itself in the dictionary, and you may say "It's got so many meanings! And it could be a noun or a verb? How will I know which is right?" Um...see it in a sentence?
That's what a spread is. A sentence. Your 5/Cups (upright or not) might be crystal clear in its meaning if you see it in a spread in answer to a question.
Also, instead of letting yourself get dizzy with all these meanings—seeing them as so different—try to find what they have in common. After all, no one, not even Biddy, says that 5/Cups means "happiness forever" right? All these meanings for the 5/Cups share common ground, even if it's a wide area. Instead of peering at each inch with a microscope, go up in a balloon and try to see what the area, in general, looks like. That will help, too.
It will also help if you read less meanings for the card and start doing small spreads. Can you remember one simple meaning (like "emotional conflict") for each and every card in the deck without using any reference material? If not, then you don't need more meanings—they're only going got do what they're doing to you—confuse and overwhelm you. Which, in the end, is all reversals are. More probable meanings for the card (additional definitions for the word). Which is why many professional readers don't bother with reversals, by the way. The 5/Cups will have that reversed meaning whether or not you turn your cards upside down. Turning card upside down just helps the reader (like spread position) to narrow the meaning down and see it more clearly.