Is a looser vagina an early sign of pregnancy?

I had sex with my boyfriend today and I wasn't nearly as tight as I usually am. I felt drastically bigger than ever before. Could this be an early sign of pregnancy? I have no idea what could have caused me to suddenly be not as tight. The only pregnancy-related symptom that I have is fatigue, but I just thought that was because I started an intense work-out plan 2 weeks ago. I have not missed my period yet; I'm supposed to get it in about 3-4 days. Please, any information would be helpful.