Dry as f*** during sex

So I never have a problem being dry. Like normally all throughout my cycle I have plenty of cm and when I’m aroused I gush with arousal fluid. Last night when I was having sex, I was wet at first and then all of a sudden I started drying up. It wasn’t like I wasn’t in the mood, because I was, I was hornier then ever last night so i know that’s not the problem. I just don’t know why all of a sudden the switch ??