I have trouble digesting

I have been experiencing this for about a month now. Every time i eat, i feel nausea. My urine is always somewhat dark, I drink around 2-3 glasses of water every day but after i eat i get a little nausea and when i walk around, i start burping and i feel better. Now i can't eat oily foods and i just want to know if this is chronic dehydration or something else.

[hyudryu]

Also, it started after i finished my antibiotics for strep throat. I didnt drink water along with the medicine so that may be the case. I dont know because i never really drank water in the past year. I would drink about a glass of water a week and i mostly drink juices and gatorade.