Well, of course it is completely up to you to decide what you want to do next, just let me explain to you in what state of learning I think you are, according to my experience.
Simplyfing a bit we could say:
1- If on average, the ratio between word forms (what Lingq measures) and word families (words as counted in adictionary) in English is1.6, in Spanish the ratio would be higher. I would say that you can consider that you the number of “word families” that you can understand passively is about half the number of the word forms (lingq words) that you know. It’s not that there are only 2 word forms on average for every Spanish word family but, because you haven’t probably seen all possible forms of each word in Lingq and because you can guess a lot of words that you’ve never read in Lingq, based on familiarity, I think it is safe to say that you have a passive vocabulary of about 5000 Spanish word families. As a comparison. I know over 33000 Russian word forms. I think the ratio of known word forms to predicted understandable word families in Russian is a bit over 4, so I may understand passively about 8000 Russian words. A bit over your level.
2- Professor Arguelles has discussed how number of words relate to level. I think he is about right. This is the relevant link:
So you are at about the 5000-word mark. According to Arguelles, that is the typical active everyday vocabulary of a not-highly-educated native speaker
An educated speaker uses twice as much: 10000
In order to “read, understand, and enjoy a work of literature such as a novel by a notable author” you need again twice as many words: 20000 words, equivalent to over 40000 lingq words.
So, is it any wonder that you strive to understand “Trafalgar”? I don’t think so.
Does that mean that you have a low level in Spanish? By no means!
You have attained something very admirable and that most wannabe language learners never reach: you are at a level that would give you a very good base for conversational Spanish.
Is it getting more difficult as you progress? No! It’s just that when you began you had a passive vocabulary of at least a few dozens of words (through similarities with English), you read texts that intended to teach you the basic 250-word core vocabulary. Gap between knowledge and goal? Less than 200 words.
As you reached that goal and even before that, you moved to texts designed to teach you the next levels. You knew more and more but the gap increased. Now you are tackling a real, complicated novel that would be a challenge for many native speakers! You know a lot but the gap between what you can understand easily (5000 words) and what you need in order to understand the novel (20000 words) is much larger than before. In fact, much larger than you’ve ever encountered and as bad as it will ever get. Notice that the 20000-word vocabulary doesn’t cover all words in the novel. It’s just what you need to know in order to guess the meaning without much effort. Besides it’s a XIX-century novel so it only requires some historical knowledge. Again, many native speakers would be at a loss in many passages.
I am at a similar level to your own in Russian. Because I’ve been talking and I have immersed myself in the language a couple of times, I can now have meaningful conversations. That fact is nothing short of miraculous, considering that most of the time, I have just read and listened here at Lingq. Do I read easily Tolstoi at this stage? No! Do I miss a lot of passages? You bet!
So, what’s the next step? Again, it’s up to you. Taking up a new language, considering that you’ve reached a decent level at Spanish and going back to the language later on may make sense, depending on your goals.
I can’t decide for you. Just let me tell you what I intend to do in Russian. Notice that I’m absolutely confident that I’ll reach my goals if I put the time and effort, because I’ve done something similar in other languages before, and without the benefit of Lingq or similar tools (it took me a few days to go through the first pages of my first novel in English, e.g.)
Well, what I am doing and I intend to do:
a) I have started activating my passive vocabulary and I plan to keep on doing so. Just as you have.
b) I keep on reading. It is getting easier but it is still difficult. I strive to understand very involved, ancient writers. I read them sparingly at this moment. If I only get the gist of a passage, I go on. If I eventually get completely lost in another one, I go on as well. Right now, I tend to read “lighter” novels, mostly contemporary “thrillers” or romantic works, etc. and combine them with medium-level texts from Lingq. I advise you to do the same: take a break from “Trafalgar”, you’re not in a hurry and you may come back later on. Get easier texts for a time, from Lingq or podcasts or about interesting topics from the internet and then get some contemporary “lighter” novels that you may enjoy. Since you like history, I recommend you Arturo Pérez-Reverte: he even has a book about the Trafalgar batlle! Maybe, the Alatriste series contains a bit too much outdated language. Try the Trafalgar book or “El maestro de esgrima” or “La Tabla de Flandes” o “El húsar”, “La Sombra del Águila” (the two latter again about the Napoleonic period"), etc.: here’s a link to electronic versions that you may purchase: Los mejores eBooks | Casa del Libro
And, if a fragment is too complicated, lingq the unknown words, get an idea of what the sentences mean but don’t try to understand every single thing completely. Just follow the main story.
c) My plan for Russian is: keep going to about 50000 lingq words, that’s about the everyday vocabulary of an educated speaker, activate half of that by speaking as much as I can. At that point I’ll be “fluent”, if that means something. Then, I’ll keep on speaking when I can, and reading, and listening. I do intend to go all the way to the 20000-word mark (about 100000 lingq words), so I can finally read involved literature on my own. Some day my active vocabulary will be half of that. And then? I may keep going, reading more interesting stuff, speaking and watching movies. You may choose to move to a different language anywhere along that road.
I wish you a lot of success, Parker