From your symptoms you seem to be developing stomach flu.
Stomach flu could have been due to food you must have had outside or road side, or water mainly you had outside. You could be having an infection, a bacterial infection in specific. I suggest you follow the following,
- You should start with taking a course of antibiotics for your infection. Take Capsule Amoxicillin two times a day for five days.
- You can take Tylenol for pain.
- Do not take any anti- spasmolytics as you need to get rid of the infection from your stomach.
- Avoid having high fiber or high carbohydrate food. Have more of proteins.
- I also suggest you to avoid having food outside, especially water.
- I also suggest you to do yoga every day, its known to boost immunity.
If pain doesn't subside in 2 or 3 days, I suggest you do a USG of abdomen to find the cause.