bloating after eating
You didn't mention your calorie intake when you are trying to lose weight so my guess is that you saw a change when you ate at your cousin's because 1) it was very different from what you'd been eating, and drastic change is often what kicks the body into fat burning mode....or 2) perhaps your calorie intake was actually lower as i would imagine while eating those things you felt were 'less than healthy' you watched your portions and didn't eat as much as you migh thave...
Your issue though is more complex than we can answer here...I suggest you speak to your doctor about it...that's the best place for advice on what may or may not be causing you extreme bloat when you eat certain foods...