What do you think?

I keep getting abdominal/ lower back pain ever since I had my baby 6 months ago. I went to the hospital, they diagnosed me with a Urinary Tract Infection. I went to my follow up appointment, it ended up going away. I am a hypochondriac and always assume the worst. I have been looking up ovarian cancer symptoms & freaking myself out. If I had something like that do you think they would have known? With all my check ups during pregnancy and my 8 week follow up?

Yes. You had a physical during your pregnancy, right? Surely any cervical abnormalities would have been noticed and looked into.
Your mind is a very powerful thing and is very capable of creating physical manifestations of what you believe to be true. If hypochondria is an ongoing problem for you, you may want to look into cognitive behavioral therapy. You need to change your negative thought patterns and beliefs about yourself, to train yourself out of this way of being.
Of course you should get your physical symptoms looked into as well, as you have been doing.
I hope you get everything sorted out!