Sad and worried did l committed shirk

I have a big problem l was thinking with my heart or saying to myself about bad things. I did not say them out loud but then l had a big doubt about my belief. When l wanted to ask allah for forgiveness l had thoughts or worry l wasn't a beliver. And emotions came to me that l didn't know if am a be liver. Am muslim Any muslim who can answer this help me out please answer ,email quickly.