Constant upset stomach??? Please help!

Hi ladies. I need some trade momma secrets here. Im 13 weeks pregnant, and while my nausea has basically subsided, it has been replaced with this horrible 24/7 tummy ache that just won't go away and the more I eat the worse it gets, but I can't just stop eating cause I need to still feed me and baby. I have small snacks throughout the day hoping that eating small portions will help, but it doesn't. I barely make it to lunch time and Im so miserable. Please tell me someone has a remedy??? What is causing this and how do I make it go away??😫