Suggest Medication For Nausea & Tiredness

Hi, I have been suffering from nauesea and tiredness from 3 days ago. I went to see my GP on the third day and he advised that I could suffer from peptic ulcers( which has been an answer from the past 7 times I have been to the dr). I was given meds for the ulcers as he also picked up from my allergy tests that I have a substance/ organism thats causing ulcers. Amongst my meds I also got anti-histamin and flygen to clear my urine as there was traces of blood on my urine. However, its been three days of taking the meds and I still have nausea which now includes what feels like shortness of breath and fatique during the evenings. In addition, my GP said he is bothered by the pulse on my abdomen which he found the first time during the exam for ulcers. I feel tired in the mornings, nauseous for the whole day and my chest feels a bit heavy. I still come to work as normal but the day is a bit more difficult to get through than normal. I also have a constant urge to burp but nothing ever comes up. Should I go back to my GP and ask for a referal for a gastroscope or just wait for the meds / antibiotics to finish and then go back? Regards, Worried