Burning sensation in my stomach.

Eleni • 26 || DH 28 || 18 month old daughter and baby girl #2 due in April
The last few days I've had some pretty bad indigestion. Today after I've eaten, I've been nauseous and have had some really bad burning sensation in my stomach, followed by big belches about 30 mins to an hour later. DH and I have been trying TTC baby number one and this is our second cycle. AF isn't due till the 20th (so this Saturday AH!) and I've had sore breast for about a week now. I'm hoping I'm pregnant, but has any ladies experienced any kind of burning feeling in your stomach after eat while pregnant? 
​Note: I've never had this problem before. My eating and drinking are the same and I exercise regularly. 
​Any advise please and thanks for your time!