Stomach getting huge... no baby?

Has anyone experienced their stomach getting bigger with no pregnancy? I look at least 2-3 months rite now. Everything else is maintaining size. I have a regular cycle and had an odd period the last two cycles. I got negative tests even tho I feel and look pregnant. Any idea what could be going on. I will see a doctor but wanted to kno if anyone else experienced this.

It fluctuates rapidly. This morning it was normal. By the end of the day it's huge. Especially after I eat and I don't eat much.