This really doesn't sound like anything serious. :) I'm 23 and I swore I had ovarian cancer last summer. I had bloating, a heavy stabbing pain in my rectum when I walked or sat, constipation alternating with diarrhea, and my weight was jumping up and down by 4 pounds. When I went to the Gyno, she felt my ovaries and my right one was sooo tender and hurt when she pressed! She said it could be caused by something on my ovary. Since my aunt had ovarian cancer I just knew I had it. I had blood tests, and 4 ultrasounds of my uterus and ovaries! Everything came back totally normal. The doctor even showed me the scan pics of my ovaries and explained why they looked perfect. My symptoms went away soon after.
Also when I was getting my urine checked during pregnancy almost 2 years ago, ( the only time I really got urine checked) I often had trace blood in my urine.
It reallllly sounds like you just have a basic cyst. :)