Scared about bladder infection and its effects

I have a 7 year old cat who was fine up to a couple of weeks ago.  I have 4 cats total.  Let me start at the beginning.  All my cats were indoor cats until nine months ago when I started to let three of my cats, Cheeky, Patchouli (7 years old, male) and George (5 years old male) outside when I was home.  They all started going outside where they pooped and peed.  Everything was fine and as my litter boxes were old I went down to two litter boxes. When I noticed a change in Cheeky where she started hissing and growling at the baby of the group Saphira (3 year old female). I went out and bought two more litter boxes.  I have a total of four litter boxes now placed throughout my home and nothing changed with Cheeky as she seemed to get worse.  I finally took her to the vet and they checked her for a bladder infection which she had and it was a very bad one as the vet told me.  They gave her a shot of antibiotics which lasts 14 days and a shot of an anti-inflammatory.  As of today, March 31, 2015 she has not shown any improvement and she is not sneezing like she has a cold or it could be allergies as I live in Florida on the west coast.  Cheeky will only stay in my room in which the other cats come in and out of.  I have seen Cheeky go up to Saphira and lick her and not hiss but then last night I was woken up to a cat fight as Cheeky was hiding under the bed and George and Saphira were bullying her which woke us all up including my 3 dogs.  When I got Saphira all 3 adult cats were her care takers when she was a kitten.  I called the vet and they told me to wait until Thursday, April 2, 2015 and see if she is any better if not bring her in for blood work.  I am scared about what is going on with Cheeky and thought maybe you could help me.  Thank you very much.

Hi I can send you to an excellent group that deals with urinary,bladder,stones ,crystals etc.they have a wealth of knowledge and are truly a godsend to everyone.Their link is

https://groups.yahoo.com/neo/groups/FLUTD/info

Hope that helps.Post New member urgent OK? Hugs C.

That antibiotic via shot (convenia) is not the best antibiotic to give for bladder infections.  My own cat had a bladder infection last fall, and since she is next to impossible to pill, we went with the shot.  It temporarily eased the infection, but then it came back within a month, so we had to go thru the whole routine again.

What I'm suggesting is that perhaps Cheeky still has the infection, and that's why the others are picking on her...they can sense her "weakness".  She was probably hissing and growling at Saphira earlier to keep her away because she was not feeling well and not wanting to be disturbed. 

Hi I have a group @ yahoo with a wealth of info about anything urinary.Bladders etc.i agree with mrs green Jeans.Convenia once made for skin problems is used widely now for everything.it stays in the body for 65 days.If you Google convenia is it worth the risk you will be horrified.in the future JMO always say NO to convenia.that group who is huge on bladder issues & extremely friendly ,helpful people is

https://groups.yahoo.com/neo/groups/FLUTD/info HTH .C..typos agian sorry(