To see a more complete and correct explanation of how the system works, see How Competitive Skill Rating Works (Season 11)
And yeah, your stats aren’t great, but you are <500 so no one should expect anything else. Looking at your profile, it looks like you could raise your rating at least some by avoiding heroes that you have poor win rates with. Your better heroes have win rates well above 50%.
Focus on getting better with a smaller group of heroes.