How should I deal with very negative feedback from some students?

Could I get some suggestion on how do I manage in such time? Is it normal for a early-age academia?

No, this is common for academics of any age. Anonymous evaluations are notoriously a valve for students to express their dissatisfaction without having to be reflective, fair, or even truthful about it. If you ask for anonymous feedback, you will need to be prepared for things that you don't want to hear. This can include very harsh judgments of your teaching quality, ad hominem attacks, or even tangentially (if at all) teaching-related comments to your person, your appearance, etc. Browsing Ratemyprof will give you a good idea what kind of statements students are willing to utter about their professors.

How you "manage" is by keeping in mind that (a) what you read is likely not the opinion of the silent majority of students, (b) that even the students that actually post hurtful feedback will often not really feel like this about you, but rather be frustrated because of a bad grade, a bad experience with your school in general, or just a difficult time in their life, and that (c) in reality, most teachers get a wide range of feedback from very bad to very good.

Also note that especially in smaller classes there can be tremendous differences between years, so having a bad evaluation in one year can still lead to a better evaluation in the following. Further, I have taken to basically ignore any feedback that has been mentioned only once or twice, and only start to take a specific complaint serious if it becomes a pattern.

TL;DR: In short, you will need to learn to not take the feedback personally.

I have a different view on such feedback and here is how I deal with it.

First of all, the anonymous comments are a great feedback and they are generally true.

Second, students, especially younger ones, are pretty bad at wording their thoughts on paper. They tend to exaggerate, be offensive or aggressive, focus on seemingly irrelevant things, draw wrong conclusions, etc.

To get the most value out of anonymous comments, I learned to ask very specific questions. My favorite ones are "What did you like the most about my class?" and "What do you think can be improved about this class?". No matter how ADD your students are, this will focus them dead on point.

If you ask anything general like "What do you think about my class?", students will get so creative and off-topic, they will blow your mind. 60 people watching you for half a year will know A LOT of things about you, you yourself don't know. If you want to learn more about yourself, go ahead, you will rarely get a better opportunity. As for me, at the age of 30 I already have a long list of things I want to improve about myself and don't want anything added to it. I especially don't want to hear about things I can't or don't want to change, like my receding hair, accent, or fashion preferences (lack of thereof).

In the examples you gave, one stood out as maybe actually useful; I hope to use it as an example for my suggested approach:

You do not teach what is in the book. Plus, you ask very difficult questions in the test. What do you want to prove?

This isn't the most well-constructed feedback, and certainly isn't polite, but I think there is a useful criticism you can extract from it. My translation:

I was confused about the importance of the assigned textbook versus what you taught in class, which made it difficult for me to prepare for the tests.

Does that sound like feedback you can maybe use? I am making some assumptions about what the student's actual complaints were, but I think you can take from this "I could make some improvements to my syllabus; maybe I need to specify more specific sections of the textbook for emphasis. I could review the textbook I am assigning and make sure it fits with how I am presenting the material, otherwise I should consider assigning a different textbook or assigning standalone reading." None of this is an indictment of your teaching ability, just a reflection that anyone can improve their teaching, and students' needs will vary. The magnitude of the changes you make should probably correlate with how common a given complaint is - if this is the only student that complained about textbook/classroom differences, probably you do not need any major changes.

In summary:

Extract useful feedback from the comments, try to ignore the emotional content as if you are a third-party observer, ignore everything else that is just rude. Most of it probably comes from your students frustrations with themselves that they have decided to direct towards you - that's mostly a sign of their own immaturity (not that all grown adults are masters of self-reflection, either). Good luck! Just being concerned about your teaching can make you one of the better professors your students will have.