Why is my stomach growing?

Question

I noticed a few days ago I have a horizontal line right above my pubic area, and my stomach seems to poke out a bit right above the line, especially on the sides. I am sexually active and have unprotected sex but I am on birth control. I have gotten my period and a negative pregnancy test so I’m not sure what could be causing my stomach to poke out all of a sudden. If I were in fact pregnant, I would be 8 weeks. When I took the test, I would have been 7 weeks and I know that it is unlikely to get a false negative at that point. 

Update:

Just an update, the line is more like a crease 

Update 2:

Since I can’t respond to the answers, I am going to post a response here. For the person who said I am not educated on pregnancy, I think it’s actually the other way around. You can in fact be bloated at 7-8 weeks pregnant which if you have any common sense, would mean your stomach looks bigger. It does not take 20 weeks to start looking pregnant so I highly suggest you do some research before commenting on peoples posts with false info when they are just looking for help. 

Answer 1

Because you eat at fast food places too often.   Seriously, see a doctor.

Answer 2

you need to see your doctor about it

Answer 3

It is clear you are not educated on pregnancy & the female body. The uterus (where the baby grows) is hidden behind the pelvic bones until about 20wks. A woman who is just 7 or 8wks will not look pregnant. 

Answer 4

you must do physical exercises, this can be liquid retention