Ive been getting migraines for years. past couple years, theyve been paired with indigestion and nausea. i feel a headache coming and get gassy and nauseous almost immediately after. the gas/diarrhea makes it so bad.why has this suddenly started?

Sounds as though if this has been going on for several years, it Has not just started suddenly. There is not enough detail here to diagnose what is going on with your stomach. It may be related to the migraines, but not necessarily. You could try some antacids to see if they help, but You should see your primary care doctor for evaluation. Good luck.

If you truly do have migraine headaches, nausea, and vomiting are very common associations. Over time, the headache patterns may vary and new symptoms may evolve. A neurologist may well be very helpful, as you may do well with a preventative intervention program.