If you have a child, you know that someone is depending on you to take care of yourself. That means being in good health so you can make good medical and emotional decisions for him or her. That doesn't mean ignoring symptoms that are troublesome, pregnant or not. And how would you know you're "7 months pregnant" anyway? For how long have you been taking pregnancy tests with negative results?
If you're pregnant and you have an IUD in place, you need to be seen immediately. If you're not pregnant and you have unexplained weight gain and feel some movement which is (miraculously) "responsive to sound," you need to be seen immediately. If you are in denial, you need to be seen immediately. If you think you stay away from a doctor because they might laugh at you, you need to be seen immediately.
When I was a women's health educator, I saw a young woman complaining of gas pains. She was in labor. Don't be that woman.
Call your doctor, or go to an Urgent Care walk-in center and say, "I have an IUD, no periods, negative pregnancy tests, unexplained weight gain, and something's going on in my abdomen." Very simple.