Am I pregnant?

Period is due in 4 days, and they are always regular. 3 days ago I started experiencing cramps all over my body. Weird muscle spasms and some stomach cramping. I've had a headache for about a week straight, along with a lower backache. Nausea on and off throughout the day, along with fatigue. Last night I began experiencing extreme heartburn that lasted through the night and is continuing this morning. today the cramping is more frequent and on both sides of my lower abdomen rather than just the left side. I am also peeing more frequently. My fiancé and I have been having unprotected sex and he said two nights ago that the has a feeling I am pregnant? Could I be experiencing early symptoms? Or is my mind playing tricks on me?!