Well, I found the way to make correct text formatting. I used
this python script.
Usage is to create separate directory for fb2 file(or files) then put fb2html.py(it's need to give it execute permissions) script and fb2 files in it,
cd to that directory in terminal and start the script
fb2html.py fb2file. After conversion into html file(with pictures also), calibre converts then html file to epub with correct text formatting.