Worried about my tummy size

I was expecting a period on November 26 but I had a missed period. I have been experiencing increase in appetite, frequent urination, and diarrhea since 1 week. My breasts are also little bit tender. I can see watery CM sometimes. I have observed a faint straight line on my lower abdomen starting at belly button and ending at pubic hair. Surprisingly, my tummy size got increased. I can’t sit comfortably on my bed. Is it a sign of ectopic pregnancy or a common pregnancy symptom. I am worried about it. My husband also noticed it and asked today ‘why your tummy size was increased’. I don’t have any abdominal pain, bleeding, nausea or vomiting.