This can't be happening

Last night, I was with my boyfriend who I haven't seen in 2 weeks. Everything was great until the sex part. I wanted so badly to be with him. But it was 'off'. No matter what he did I just couldn't even get to the point where I was even in the mood. Before I went to his house, I couldn't stop thinking about him. When he saw me, grabbed me and carried me to the bedroom, I melted. And I couldn't even enjoy the sex. Normally we have the most amazing sex ever. Am I over thinking this or could something be wrong with me?