Any explanation??

Autumn • I`m 19 years old. I`ve been with my boyfriend about 5 months. We`ve known each other for over 4 years. We`ve been trying to have our first baby for the past 3 months.
I've been throwing up and very nauseous lately. My boyfriend and I had unprotected sex all of my fertile days. My period is expected for the 23rd. Could I be pregnant???