I Am Wondering If I Could Be Pregnant. My Last

I am wondering if I could be pregnant. My last period was Jan 17-23. I had sex on Jan 28th. My previous period before that was Dec 12-19. I am displaying some symptoms such as tender breast. My nipples are extremely sensitive. I am very tired all the time and I feel nauseous the last week or so. I am 20 years old and have no medical history.