Platlete count in my dog

[Jeepbrie]

Hello, I am just lookng for any information that anyone may have. My dog had her vacinations in September 06, she is 4 , so she has had her shots for 3 years. She had a bad reaction to her vacinations which resulted in low low low platelette count. She can no longer receive any vacinations. She was on 80mg of Prednison for 1 month and then we lowered the dosage and all teh bruising and bloddy noses were gone. her platlette count was where is should be. On Dec. 7th 06, she was no longer on any meds. I went back every 2 weeks to test her platlette count. Everything seemed to be going gerat. Until Feb. 1st 07. She started to bruise again and got a bloody nose. She is now back on Prednisone. Her platlette count is back to normal. However, the side effects of the Prednisone is really getting to me. She has lost control of her bladder. She is on bladder control pills, but not working all the time.
Does anyone know anything ablout what may be causing the low platlette drop?
Anything would be helpful. I am at a loss. She i only 4.