Help with drug clarification

Patient: Hello, i am 28 years old computer programmer and please i have stomach pains that has being for over two weeks mostly before i eat. Once i eat, it suffices and then starts again seriously. I was told to keep taking lots of milk and yoghurt, however, this evening it was very serious that i rushed to meet a nearby pharmacist who told me that it’s ulcer symptoms and recommended the below:- Clarithromycin (twice a day – 500mg)- amoxicillin/clavulanic acid (twice daily)- omeprazole (once daily, 20mg)But I am scared using these drugs because i don’t know his competence and also after reading about their side effects on the internet. Please kindly advice – should i go ahead?Please help me asap. I am waiting with my drugs at hand. thanks a lot sir/ma