what's a sadness!

Things, that I wrote below, are maybe a little bit difficult to understand. My manner now is quite complex.
I don’t know why everything is getting like that. I felt very sad, but why?
Why do I have lots of thing to be sad like that? I was unhappy when someone that I hate turned back. I didn’t reallly want to say anything to her and maybe neither she.
I was a little bit angry when someone didn’t keep her promise. Did I probably miss something when I wore the headphones? I’m not sure. While I answered a phone call from my sister, she was preparing to have a bath.
And that phone call made me a little bit sad and there was something, that was very difficult to understand. It seemed, that my sister and I were not so close with each other as we used to be, when we were children/kids. The busy life created our distant. I suddenly realised that my sister never gave me a present at my birthday.  It worths for me to say. I though don’t need her present but her heart. And I didn’t receive a present when she was paid her first pay….
She said to me that our mom was sick. There’s a fever in the country at the moment. I called to her to ask about her heath. However, she wasn’t so happy when she answered my phone as usually. I didn’t know what’s happened. We made only a very short conversation before we finished the phone call.

what's a sadness! How sad!

The things I've written below may be bit a little difficult to understand, as my current mood is quite complex.

I don't know why everythings has been getting like that. I've been feeling very sad, but why?
Why do I have lots of things to be sad about like that? I was unhappy when someone that I hated turned back. (I don't know what you mean.) I didn't really want to say anything to her and maybe she didn't either.

I was a bit little angry when someone else didn't keep her promise. Had I probably missed something while I wearing the headphones? I’m not sure. When I answered a phone call from my sister, she was preparing to have a bath. (I don't understand this either: she called you, but she wanted to have a bath?) 

So that phone call made me a little sad, and there was something that were very difficult to accept. It seems my sister and I aren't as close to each other as we used to be when we were children. Our busy lives have created a distance between us. I suddenly realised that my sister had never given me a present on my birthday. It worths for me to sad. (I cannot understand this sentence.) I though didn't need her present, but her heart. What's more, I didn’t receive a present when she received her first pay…

She told me that our mom was sick. There's a fever going round in the country at the moment. I had called for her to ask about her healthly. However, she (your sister or your mother?) wasn’t as happy as usual when she answered my phone call as usually. I couldn't know what was happening. We had only a very short conversation before we finished the phone call.

I'm sorry to hear about this frustration. As for the writing, you do need to learn the other past tenses - this is pre-intermediate level grammar. I hope real native speakers correct your future posts, as I don't find the other correction on this page useful at all. Too many mistakes by a B1 level (not C1) speaker.

One more suggestion, if you are serious about your English: please write your name as <em>Doong</em> or <em>Doung</em> (or simply <em>Du</em>).You can look in an English dictionary to see what your current spelling looks like, to native speakers.

Best of luck.