Right. He didn't actually lose his feelings toward her. The void was going to take his most important feeling towards Sakura but she cried out his name and created the new card. (Hope combined with the void.) and then he was fine. Because it kinda destroyed the void that was around Syaoran. Lol. Best way I can explain it. That's why he said "Even if I lose this feeling, I will come to love you again." So basically he said that because he thought the void was going to take his feelings away but yeah back to what I said before, she called out his name and well yeah..
Its not a dumb question because I was rather confused when I watched the movie too.