I’m having trouble with Christianity.

I’ve been Christian my whole life but recently have been getting really scared of judgement day and God saying he never knew me. I know Jesus died for me and I know that God is real, I don’t know why I’m worried. It feels like I’m only believing just to go to heaven but I know that’s not true. It’s just a weird thing that appeared in my head recently and it’s affecting my relationship with God. It’s gotten so bad that when I just think of God I get worried. Any advice?