Stomach, headache, dizziness help please?

So i'm 19 yrs old and weight like 99 pound I hadn't been feeling to well and I ha these stomach aches and I didn't have a appetite so I was losing weight so I went to the doc they did an ultrasound she said my gall bladder had sludge in it. And I'm a little nervous. So I had got and egs and she said my tummy was inflammed and I needed to watch what I ate also my vitamin d levels were low, now my stomach kinda still hurts and I feel dizzy and weak sometimes just tired, people say it's all in my head and I'm stressed but I don't be wanting to go to work cuz I'm just not feeling it. What could this be