Worried I have a brain tumor/ cancer.

Hi, I'm hoping to get some advice. I've been having quite a few medical problems lately and I'm constantly stressing over it now and worrying myself sick. Sorry in advance that this is long and kind of all over the place.. A month ago or so I was having chest pain on and off and my doctor put me on medication for an ulcer, which seemed to help some. But then a little over 2 weeks ago I started having horrible upper abdominal pain, I was seen in the ER three times before being admitted for very high liver enzymes and high bilirubin. They tested me for hepatitis, which was negative.