But I think it doesn´t have anything with them because there is "bitcoin network fee".
Can this be because of many unconfirmed transaction which are now on network or what can be it?
It could be but im not sure about this wallet. Choose other wallet from bitcoin.org official website section choose your wallet. There are wallets that let you adjust fee as you like
, so you choose to pay 1$ or 10$ or 100$ or 0.1$.
I hope you choose better wallet, i can recommend fast wallets, electrum and multibit and a slower one bitcoin core.