Pain in Stomach

I’m 40 years old and have one child. I saw the doctor a month ago because maybe 4 times in 2 months I had bad pains in my stomach that felt like contractions for 3-4 hours and the only thing that helped was muscle relaxers. My bladder is full a lot and a lot of urine comes out each time with no pain. I have an ultrasound on Tuesday but I’m terrified. My doctor felt my stomach and said he couldn’t feel anything with my ovaries but I’m terrified of cancer. Any ideas?