Accepting a box of sweets from a non-Muslim

I am in great trouble. My aunt has brought a box of sweets which some non Muslim has given us on the occasion of Diwali (non-Muslim festival). I did no know about it. So I have taken sweets from it and when I took one sweet from it my mind struck that this might have came on the occasion of Diwali and when I asked her, she told me yes this is on the occasion of Diwali. So I got confused how to get rid of it so I made a plan that I will take one bite of it to show other family members that I have eaten it and after spitting all the sweets which I had taken I felt that very little part of it went inside my throat which I was not able to remove. So my question is have I done kufr or shirk. Believe me, I didn't want to eat that sweet but since I have taken that sweet so I was afraid that if I reject this sweet in front of other family members, they start pinching me. I love Allah very much and also want to be free from shirk, bidat and haram things.