@Mountaindewed, I agree with BethRags. What you've been consuming sounds like a strong potential cause of stomach issues. I'm not saying you should just ignore the issues, though, but I wouldn't immediately be that concerned about something as bad as cancer. You might want to talk to your doctor(s) about the cough syrup and antibiotic, or at least your pharmacist. I can say that neither my doctor nor pharmacist would ever want me to take cough syrup with my psych medications, or even an OTC medication like Tylenol Sinus/Allergy. And once when my psychiatrist learned I had been taking Sudafed a lot, I got my butt chewed out, and a particular pharmacist even refused to sell it to me. At the time, it seemed a shame because it worked great and made me feel wonderful, but it was ultimately drug abuse/self-medication. Having been down that road, I can tell you it's not a good one to walk.

I've learned that antibiotics often cause stomach distress in people. And depending on the tea, I sure think it could be a culprit. At least with the whole combo. In fact, I cannot drink plain hot black tea (i.e. orange pekoe/black, English breakfast, Earl Grey) without stomach distress. Or very strong black tea iced tea. I can only drink them with milk in them or very weak. Sometimes the combo of black tea and lemon juice is especially tough on my stomach. When I was much younger, I felt very sick when drinking it plain and/or with lemon juice. See point #4 in the article Side Effects of Tea: 9 Reasons Not to Drink Too Much