Hi and welcome to the forum.
First, as well as in real life football, you can't win every game here. Long unbeaten or winning streak is possible, but not endless.
To be able to help you, for beginning we need to see screenshots of your team, tacics, detail info about matches you lost (statistic, formations used, players rating). We will try to detect where is problem, where you made mistakes or were you trolled by game etc.