How are you? i hope you are doing better now. This is most probably due to something you ate or drank, that was contaminated. What i suggest is you take lots of fluid keep yourself well hydrated. Take ORS
formulations or you can prepear it yourself by adding 1 teaspoon of salt and 4 spoons of sugar in 1 liter of boiled water. This will replace your salts and provide you the energy you need.
Take soft diet
for a while, soups and such. for your problem with gas try taking small and frequent meals avoid food with oil and fermented products. It is good that you take fiber keep doing that.
This problem with run its course and cure itself. Just keep yourself hydrated and you will start feeling better in 3-4 days. If you have any further problems do let me know.
Take care of yourself