I took gas x. i lay down and now my heart is beating like crazy to the point i cant sleep. is this a side effect or should i be concerned at all?

? Side effect: When used in small doses, no common side effects have been reported with this product. Seek medical attention right away if any of these SEVERE side effects occur: Severe allergic reactions (rash; hives; itching; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue). Ref: https://www.drugs.com/cdi/simethicone.html