Pregnancy or something else?

Ive been trying to get pregnant for 6 yrs now. I have a new boyfriend who was my best friend first. He tells me he wants to be a dad so we are letting things happen without protection and during my fertile weeks. My period last month only bled 2 days and spotted very little for 3 fallowing days. Makeing the period 5 days total. We did the deed the day before predicted ovulation and 2 days prior to ovulation. All month ive been getting dizzy, nausea, boobs hurt, and i have this pressure with light pain where my uterus sits. Ive had children before so i know the feeling. What are opinions on what the pressure could be? Its obvious enough for concern and the fact yesterday had full blown period back and tummy cramps but no period wich is due the 12th its the 4th. Thank you for advice opinions etc.