Hi anu..congrats on your marriage, as you have missed your periods and getting these weird symptoms, so first of all perform a urine pregnancy test by self at home, this would confirm your doubt whether you are pregnant or not.. If its positive, early pregnancy is the cause of your symptoms because gastritis is quite common in pregnancy due to hormones. but if pregnancy test is negative, you should get a gastro evaluation done if these symptoms are quite bothersome..simultaneously take tablet sompraz 40 empty stomach once a day(or twice if symptoms are severe) for 14 days for relief..