I Have Had This Reoccurring Pain Under My Sternum Whenever

I have had this reoccurring pain under my sternum whenever I eat anything. It went away completely while on vacation for a week in Las Vegas. I ate like crap there, but was walking at least 6 miles everyday and drinking a TON of water. On my 2nd day back, I ate a grilled chicken breast and grilled potato with a little olive oil on it. It felt like I had the worst bubble of gas under my sternum from 4pm until this morning. I tried some plain toast and it made it worse. I'm making a doctor appointment, but in the meantime, what can I do? I have low blood sugar so I have to eat something, but I'm scared to as the pain is horrible. It's like when you drink soda or something too fast and you get that big bubble in your throat, but it's all the time and right in the middle of my chest.