From what you are describing it doesn't sounds like a hernia... Here is a description of a hernia....
hernia occurs when the contents of a body cavity bulge out of the area where they are normally contained. These contents, usually portions of intestine or abdominal fatty tissue, are often enclosed in the thin membrane that naturally lines the inside of the cavity. Although the term hernia can be used for bulges in other areas, it most often is used to describe hernias of the lower torso (abdominal wall hernias).
http://www.emedicinehealth.com/articles/13842-1.asp
From what you are saying.. It sounds as though it may be a pinched nerve since you state leg cramp and/or possible kidney infection or bladder infection.
There are a number of symptoms associated with UTIs. Bladder infections are characterized by an urgent desire to empty the bladder. Symptoms include frequent urination, burning or pain during urination, bladder spasms and the feeling of having to urinate even though little or no urine actually comes out. In some cases, you may have bloody or foul-smelling urine, and maybe a mild fever. A kidney infection may involve more serious symptoms, including fever, chills, and nausea. There may also be cloudy or bloody urine, abdominal pain and burning, and frequent urination. Most people with kidney infections also experience back pain just above the waist.
http://www.coolnurse.com/bladder.htm
If those are the only symptons.. is it possible you pulled a muscle or have a pinched nerve? If this continues for more than 48 hours I would see a doctor to rule out any type of infection.. and lean towards a pulled muscle and/or pinched nerve.
Good luck, if you need anything else please feel free to ask
Healthcare Expert
17+ years, Healthcare Expert