Dear friend,
Yes Cleo needs to see a vet. While this is not as dangerous as if she were male, it is quite painful for her.
In addition kidney toxins are being released into her bloodstream.
Your cat may have a urinary tract infection.
UTI's must be treated with an effective broad spectrum antibiotic like Clavamox or clidamycin and for a long enough duration so all bacteria is eradicated. If not, they will refluorish, stronger and more resistant and re infect her . In addition, the bacteria can become tolerant of the same antibiotic so the medication should be varied for best results.
http://www.sniksnak.com/cathealth/cystitis.html
http://www.associatedcontent.com/article/32507/feline_cystitis_symptoms_and_its_treatments.html
Please let me know how your baby is doing. I hope she is feeling better very soon.
Sincerest best wishes,
Terri
Feline Healthcare Expert
Expert in feline health and behavior. 20 years experience with cats.