Re: You are not a Muslim.
People call me often non muslim on different occasions without even knowing me.
Doesn't bother me anymore.
They can't read your heart and they're not with you 24 hours a day, how can they judge you? They're not the angels on your shoulders writing down everything, they're not Allah himself. They're not your hands, feet etc. which will talk on Judgement Day about everything you did.
Don't let people like that get to you. Just make sure you are following the right path and don't do something if you have doubts about it being halal.