Unconscious, Feeling So Weak. Serious?

Since few days I feel unconscious, week, sleepiness, bitter taste of Mouth, sometime nausea. In last 7 8 months I am unwell first had stomach infection cramp, frequent motions. After that again and again I am having stomach infection as per doctors done infection course 7 8 times. Lost 8 Kg around weight as well. LFT,KFT, USG OK. Grade 1 fatty liver. 15 days back I had again stomch infection as per Dr that time I had cramps, body shivering, nause. I am so worried what happening to me now my body isn't in my control not able to do work and concentrate. Consulting gastro he is saying no need for test it's IBS. But I am worried whether getting sick again and again is cause of some serious issue? Need Dr who can get in detail analyses and can get me out of all this please. I am from Noida. Should these shows something serious ?