What is the cause of my sudden vomiting and sudden onset severs back and side pain?

Yesterday I began vomiting the entire contents of my stomach. The nausea came on suddenly and was gone just as quickly. A bit later I had some water and about ten minutes after that I vomited again. This became the pattern, all day long I would drink water (even if I just slowly sipped a little bit at a time) and then 10 minutes to half an hour later I would vomit it up. I tried to sleep that night, sipping water here and there, but I couldn't shake the pattern of vomiting. Then, lying in bed feeling dehydrated and miserable, a dull ache in my lower back began, similiar to menstrual cramps but more severe (and I am not menstruating). It has progressed over the ped two hours and I have vomited twice more since it began, mostly bile. It is in my lower back and now also my sides, and sometimes it radiates into my lower abdomen. I have been able to urinate just fine, however I have not yet been able to have a bowel movement. I just want to know if anyone has had a similiar experience and what you did to treat it.