Swollen vagina in the mornings

Patient: The past few days, when I wake up in the morning, the outer “lips” & my clitoris are swollen & sensitive. It doesn’t hurt at all. The sensitivity is almost like the sensation of if I was extremely aroused. The swelling goes down within 30 minutes. It’s possible that I’m pregnant but it’s too early to test. Is there a possible explanation for the swollen vagina?