Very Confused

The spotting got heavier and I began discharging large clumps of I guess tissue. This went on from about 8pm last night until 10pm tonight. I went to the hospital this morning on my fiancee's insistance. It was a terrible experience. First they told me I wasn't pregnant, then all the other nurses that saw me kept asking me if I had taken a pregnancy test. I told them I had and that the doctor said it was negative. I had my first gynocological exam ever, and had to have it done by a male doctor. He said there was abnormal discharge. Then he felt my stomach and there was a lot of pain in the right side of my abdomen. He sent me for a cat scan because he thought I had appendicitus, or an ovarian cyst. Everything came up normal. After six hours, he came back and told me I was perfectly healthy and had no explanation for the pain, the bleeding, or the pregnancy symptoms. He said I had dysfunctial uteran bleeding, and that it was probably part of my regular cycle.
The clumps continued all day, and the pain in my side got worse. I felt sick, and had a headache all day. Then early this evening the bleeding stopped. About a half an hour later it started again. Now, the bleeding has stopped again.
I am so confused at this point that I can't sleep. I asked if they could tell me if I had been pregnant, and they said they could only tell me if I was at that time. But here is the thing I don't understand, they never asked to see what I was passing, they never gave me a blood pregnancy test, just a urine one, they just seemed to want to run unnecessary tests that I knew weren't needed. A woman has a certain level of intuition about her body, and I know there is something wrong. I was so upset when I left there, because I still had no answers.
This is certainly not my regular cycle, and it is certainly not normal period bleeding. It is bright red or pink in color, and there is still very little blood other than the clots which are dark.
At this point i'm ready to just give up and ignore it. I don't know what else to do. If anyone has any advice i'd appreciate it.