Brief Answer:
Following suggestion......
Detailed Answer:
Hi back, 
Thank you for following up. 
I am glad to know that all your tests were negative, meaning that you do not have any organic problems. 
In my practice, I usually advise patients confirmed with diagnosis of 
IBS to: 
- be careful with the foods they consume
- control stress
- get more involved in physical activities. 
All these will help improve intestinal movements. 
With regards to the diet, usually, in my practice, I do not suggest a strict diet as patients find it difficult to follow for long. 
The most important thing is to consume foods high in fiber and drink more water. 
A low Fodmaps diet is a very specific diet restricting foods high in Fermentable Oligo-saccharides, Disaccharides, Mono-saccharides and Polyols. These are a  group of specific carbohydrates that are being  poorly absorbed by the intestines. While they are digested by the bacteria in the intestines, gas is forming aggravating the symptoms.  
The main idea is to increase the water content in the feces without forming excessive gas. Restricted foods include: 
- Fruits, high fructose 
corn syrup, honey, etc. (high in fructose)
- onion, wheat, garlic (Fructans = inulin foods)
- Dairies (lactose)
- Beans, legumes, lentils, etc (high in galactans)
- Polyols sweeteners (
sorbitol, xylitol, maltitol, mannitol, ettc. and stone fruits = nectarines, plums, peaches, apricots, cherries, etc.
This diet is a prescribed temporary (up to 2 weeks) and not life time. That's why I usually recommend life-time foods or diets. 
Hope it was of help!
Dr.Klerida