What am I doing wrong?! (hair damage)

It's quite possible the only thing that will work is a really good hair cut. Bite the bullet and get a good chunk cut off. It might be difficult, but it'll almost certainly make it easier to grow. You need to get rid of as much of the damage as possible so it stops breaking. Damage travels up the hair and that's why it keeps breaking even though you get it cut.

Also, instead of using shampoos, you should think about switching to conditioner only washing. It's a lot better in the end, I promise 🙂

Bleach damage is cumulative and permanent, so if it is damaged a cut is the only real solution.
Are the shampoos and conditioners you use silicone free? Many 'repairing' conditioners are very silicone heavy (they don't repair the hair at all, just mask the damage) which can prevent water and oils from penetrating actually making the true condition worse.
A good clarifying shampoo will get them out, and then you could try CO washing with silicone free products.
If you clarify a couple of times, dont add conditioner and let your hair dry, you will see the true condition of your hair, which might help you decide what it needs.
Other things you can try are Olaplex (no idea if it is available in Croatia, sorry) and balancing protein treatments with moisturising treatments. Joico k Pak deep Penetrating reconstructor or aphogee 2 step are good protein treatments, always follow with a hydrating treatment, as protein can make hair more brittle

Please don't take those Biotin pills in the hopes of it helping the ends of your hair, it physically can't. As soon as it leaves the scalp it's dead keratin. Biotin will only effect the new growth while you've been taking them, and even that's debatable.

You basically need to baby that bleached, damaged hair, no detangling when it's wet and perhaps try a Tangle Teaser-type brush as they don't rip at the hair as much.

I echo the suggestions to cut out silicone use and try conditioner-only washing.

Oh im taking biotin for new hair, i know it wont help the damaged parts. I dont know if it's doing anything to new hair, but it cant hurt, ey? :p

I tried washing it with only conditioner but it was becoming really disgusting looking and greasy :/

The problem is that i cut it, and it looks and feels good and healthy and smooth and nice, and after few weeks or months ends start breaking off again. So i thought maybe im doing something wrong cause im not putting anything damaging on it ._. I do have tangle teaser, i barely use normal brushes.

We have Olaplex, it is extremely expensive and i dont know how well it works and if it's worth the money, I'm reading a lot of good but also bad experiences. I will try to get my hands on aphogee, I found it on ebay, every time i consider buying it, i cut little bit off and then my hair looks and feels fine so i give up on buying it XD

But how much have you had cut?

With conditioner washing it can take weeks for it to settle down for some people. But you also have to find the right conditioner. I can get away with super rich conditioner, but most people need a thin cheap conditioner to wash and a slightly richer one to condition. It really is worth sticks with it.

I would take off about 1-2 cm every time i would notice my hair is getting split ends and starting to break off, depending on how much i saw it was damaged.

How are you brushing it? Bleached hair is extremely susceptible to mechanical damage, so needs to be treated very gently when washing and brushing/combing.
If it is damaged from over bleaching it may be impossible to save though, and cutting all the damage out now will mean you have longer hair in a year.
Biotin doesn't make hair grow faster, it will only affect growth if you were deficient in Biotin to begin with. Eating a healthy balanced diet will ensure you get enough biotin without resorting to supplements. Biotin supplements can have some nasty side effects.

Just normally i guess, it does not tangle cause my hair is very fine and silky, even if it does tangle by any miracle, it's not trouble to brush it out.
When its wet i usually try not to brush it, if i do i either use wide tooth comb or tangle teaser. And ofc i always start from ends and working my way up.

I have some health issues, my body does not get nutrition from food the way most of people are, so i have to take vitamins pills every day for the rest of my life, i also take b12 injections once a month cause my body is not getting it from food at all, so that's why i started taking biotin, hoping my hair would grow stronger cause, like i said, it's really thin fine hair. Should i stop?

My goal is to get my hair 20 more cm longer (boob length), then i can cut the dead ends and let it grow and it wont be as short. I hate it at this length (shoulder) it does not suit me at all and i've been stuck with it for the past 3 years. 🙁 Thats why i reeeeeaaally dont wanna cut it 🙁 I'm even ok with a bit of damage at the ends before it grows out, but the way hair works little damage grows into a lot in no time ._.

If you are not absorbing B vitamins, you may well be deficient in biotin as well, so don't stop taking it if you aren't having any side effects.
Your health may be making your hair weak, a good diet is the key to healthy hair.
You have my sympathy, my daughter has absorption issues/gastroparesis.

Even then, I'd still say get more cut off than 1-2cm. 1-2cm is not going to cut off enough of the damage and you run the risk of it damaging the unbleached hair as it comes through if you keep having that small amount off each time. Once you have split ends it's essentially too late. It's like an iceberg, there's way more damage that you can't see with the naked eye further up the hair shaft. You really need to get at least 5cm off. I know it's hard when pure trying to grow it, but it's better in the long run.

Hi there. I have had a few friends whose hair was so damaged, they had to literally chop it all off into a pixie and start growing it over again to get healthy hair. Not sure if your hair is that damaged, but if it is, could be exciting! Pixies are fun!