Yes, it could be the gum, if you have fructose malabsorption (a very common problem that many people don't realize they have) or some FODMAPS digestibility issues (closely tied with IBS)
Here is an exerpt from one site:
Sorbitol (C6H14O6), also named glucitol, is a sugar alcohol (polyol) derived from glucose. It is used as an artificial sweetener in diet soda, sugar free chewing gum, other sweetened products, or as a moisture stabiliser in baked products. On labels it can be referred as humectant, sweetener, emulsifier, it may be ’hidden’ in sugar alcohols (polyols), or denoted as E420. It may be present in medical syrups for children, and it is also used as a laxative.
Sorbitol naturally occurs in stone fruits (plums, peaches, apricots, cherries, etc), apples, pears, grapes, and may appear in high amounts in dried fruits, like prunes, raisins, figs etc. It also appear in related fruit juices, jams, etc (foods high in sorbitol) (9,10). Sorbitol is partly absorbed in the small intestine – it’s calorie value is 2.6 calories/g (sugar has 4 cal/g).
Sorbitol seems to slow absorption of fructose. If ingested in excess, it drags water into intestine and causes osmotic diarrhea; 10g of sorbitol (1 stick of chewing gum contains ~ 1.25g of sorbitol) can cause prominent diarrhea in a child. Consuming 20g of sorbitol daily was reported to cause chronic diarrhea and weight loss in adult. Persons with fructose malabsorption are often excessively sensitive to sorbitol.
Source: Low Fructose Diet in Fructose Malabsorption | Healthhype.com