I think in both the languages. There are people i only talk to in a certain language. So if i am in that company of people or dreaming about them. I think in that language. It flip flops.

I'm fluent in 3 and I think in all 3 of them depending on which setting I am in. For example, if I am around spanish speakers all my thoughts are in spanish, same for the other two.

In serbian, sometimes in english

That's awesome man! I'm taking Russian classes in University and I really want to become fluent in Russian so I can go back again.

I'm not bilingual yet so of course I only think in English (unless I'm doing work for Russian class). 

Notice how I said "purely without words." I'm very familiar with different learning styles and how they can be associated with thinking. I'm well aware that some people lean towards being visual learners/thinkers. However, my argument (and again this is a personal opinion) is that as long as you know a language, you will have a stream of words going through your head at any given time.

I believe that you are  predominantly a visual/abstract thinker. But I absolutely refuse to believe that that completely substitutes words.

As I said I only hear the words in my head when reading/writing (although faintly and accompanied by the images I picture) and perhaps when remembering/imagining conversations. If you don't want to believe me, whatever...

I just asked my girlfriend and she actually laughed at the concept of thinking with words. She said it would be 'time consuming'. So at least I know I'm not weird...

I seriously always thought that only happened in movies/series, when you hear the character's mind's sentences while they gesticulate. I never until know believed people actually do that (and apparently a majority).

Can you give me some examples of what you tell yourself?

I'm fluent in danish (my native language) and english, but I don't really pay attention to what language I think in. I think I think mostly in danish, with some english thoughts from time to time, but it's really just guesswork.

I don't know about moza but after thinking about it (lolpun) I think people experience a mixture of both

For instance while thinking about your post and how I was going to reply to it, I thought in words 100%, just assembling ideas and sentences with thought. Also, I can intentionally think about something and it'll feel like me talking

I also realized that I don't actually stop and think about much throughout my day, if at all. If a random thought does happen to pop up in my head (especially if unintentional) then it usually represents itself as an idea/concept rather than words/sentences, especially if the corresponding word is unknown/hard to describe, like the face of a pretty girl whose name I didn't know, the word girl didn't pop into my head either, just the face. Regarding feelings like hunger/thirst or heat/cold and the sort, I doubt most people would think up sentences for that stuff either

One example is just now I was thinking of what I was going to have for breakfast tomorrow, the idea of sunny side up eggs with a runny yolk immediately popped into my head but my corresponding word for that thought was just 'eggs'. When I remembered that I wanted extra salt I saw salt and thought 'salt'. Is it different for you?

OT: The fact that the words were 'eggs' and 'salt' means I was thinking in english lol

Welsh but no one here knows what that is.

Good luck and SPEAK with native speakers LOTS. Russian is a pretty crazy language, and only speaking it will hand you the reins of control, mainly thanks to the big conjugation, suffix, and intonation focus in it.