It could be due to hyperacidity
Thanks for your query.Based on the facts that you have posted it appears that you are 26 weeks pregnancy
and having problem of stomach pain ,heartburn
since last 2-3 days.
This is common during advanced stage of pregnancy due to pressure of gravid uterus
Please take Hr receptor antagonist like Rabiprozole or Pantaprozle twice daily .
Continue to have small frequent meals preferably juices,fruits and soft diet
Elevate head end end of your bed so as to reduce pressure over stomach.
I think this should work fine and resolve the problem.
Hope I have answered your query. If you have any more questions please feel free to ask me I shall be happy to help you .
Thanks and Regards.