Sounds exactly like candida. Unfortunately if this is the case you will most likely get no assistance from a gastroenterologist. Also, homeopaths doctors usually try to give you homeopathic remedies which do not seem to really do much for candida.
What you need to do it get on a candida diet. Take raw garlic, probiotics, maybe p & b shakes and caprylic oil. Take vitamins with extra vitamin c , zinc, calcium and magnesium.
Candida robs the body of valuable nutrients making you feel drained and horrible. Your intestinal symptoms are classic candida. And if they came on after Antibiotic use you can be vcertain that is what it is.
Vitamins are extremely important. A p & b shake consists of psyllium to clean out the colon, benotnite clay to absorb toxins and carry them out of intestines, and you can add liquid caprylic oil to this shake , drink twice a day. It will kill candida and flush you out and get you back on track.
If you do this right away you will get better faster...much faster. Do NOT wait. The longer you give candida a foothold, the harder it will be to heal.