Could I be pregnant?

My boyfriend and I are not currently trying to have a child, but it would not be a bad thing if it occurred. Our only form of birth control is pulling out, and we have sex at least 5 times a week. I have a bit higher of a sex drive then my boyfriend (I typically want to have sex at least once a day) and I noticed randomly last week that it had been a few days since I had even thought about sex. Around this time my face also started breaking out (something it hasn't done in years). Earlier this week I began experiencing diarrhea.This symptom hasn't really gone away but isn't as bad as it was. I then started feeling nauseous on and off throughout the day for the past three days and also found myself feeling very faint at work, as if I'm about to pass out. Two days ago when I finally told my boyfriend how awful I felt he just looked at me and was like "your pregnant", I laughed it off because I really didn't think I was. This morning as I was making coffee for the two of us I mentioned to my boyfriend that the coffee just hasn't been tasting right all week, and apologized to him for making it gross every morning , he then looked at me and was like if I wasn't sure before I definitely am now. I finally broke down and bought a first response pregnancy test, which came back negative. Since my period came a few days early last month, I'm not entirely sure when the first day of my missed period would be. I calculated it and today could be anywhere from 6 to 10 days prior. A part of me is telling myself that it is way too soon, and that I must be pregnant, but another part of me (that started getting really excited about the idea) doesn't want to get my hopes up. I guess I'm just wondering if this sounds like I could be pregnant, and if so when should I test again?