I Had Mild Stomach Ache Few Weeks Ago. It Was

I had mild stomach ache few weeks ago. It was like occasional twisting pain starting in the upper abdomen and covering the whole abdomen (in max 3-5 seconds). My motions were OK. When I visited a doctor, he said, I have stomach infection. I took antibiotics (for 2 days) and recovered.
Since last three days, I have the same problem repeating. 3 days back I had two bottles of beer and then had to go to the toilet for 3 times (motion was semi solid to liquid at the end). Last two days I also have pain just above my hips. I am finding it slightly painful to urinate. I thought that I am suffering with stomach ‘heat’ and drank coconut water thrice since yesterday. Yesterday night was OK. No pain. But it started again today morning. I feel OK after going to the toilet (motion). But this time i had a burning sensation (medium intensity) in my rectum area. Got one bout of dizziness for 4 seconds.
I feel like all the energy has been sucked out of my stomach. Please help me diagnose my problem correctly. Is it infection? Or something worse.