Severe stomach pain at night

pb&jojo

Hi all. I found out I was pregnant the day of my missed period (Wednesday). I suspected the pregnancy because of my constipation and gas (which is unusual for me). Since I found out, I have been having off and on mild cramping during the day, but at night (or whenever I lay down) I get waves of extreme stomach pain. It is overwhelming and keeps me up all night. If I can go to the bathroom it will alleviate the pain for some time, but eventually starts up again. I am worried....should I be? I don't know if its cramping, or just the constipation. Anyone experience this? I am in week 4.