I don't know, what meto do inwith my life

I was planning to enter the study philology, but because of one failed exam, Iit's doubtful that I will get therit a good choice.... Now I'm thinking about (going to/ applying to) the conservatory

"I doubt I will get there" is unclear. It is grammatically correct but it could actually mean a couple of things

I don't know, what me do in my life

I don't know what I will do with my life

I don't know, what meto do inwith my life

This is such a common phrase in English that you can always use this wording!

I was planning to enter the philologygo into linguistics, but because of oneI failed one exam, I doubt that I will get there...be able to. Now I'm thinking about theentering a conservatory.

The word "conservatory" sounds strange here by itself. You might want to say "a conservatory of music" if that's where you'd like to go. You can say "philology" if you want, but that's not a very common word in everyday conversation. We would probably say "linguistics" instead.

I don't know, what me do in my life

I Don't Know What to Do with My Life

I was planning to enter the philology, but because of one failed exam, I doubt that I will get there.... Now, I'm thinking about the conservatory.

In the US, we use the phrase "to go into" which means "to enter": "I was planning to go into philology".
Also, instead of "I doubt that I will get there", we can say: "I doubt that I will be able to (get into philology)".
Naturally, I would say, "I was planning on going into philology, but because I failed one exam, I doubt that I'll be able to...".
Bonus: What I would say to a friend: "I was gonna do philology but I failed the exam and now I think that's out the window..."