Excessive Sentence? Sentencing, Plea Bargains

Two years ago I wrote a hot check for $33. Shortly after that my family and I moved to another county. Not knowing or realizing there was a check. Earlier this year another infraction with the law, bit me in the butt. This charge was approximately 7 years old and I think we fought it for the whole 7 years. It is completely unrelated to the check and is not even a similar crime. I was finally sentenced to the first charge which was a class A misdemeanor. During this time, i found out that I had a warrant for the check and had to bond out...$5,000 bond. Definately excessive for a $33 check. I bonded out after my sentence for the first charge and had the arraignment last week. I plead guilty and was sentenced to 10 days in county jail with a $396 fine and court cost. This is after restitution was made on the check. I still cant believe all of this. I am not a criminal and dont even have a speeding ticket. The state in which all of this occurs is Texas. I have done some research and found out that I could have gotten 18 months. Is there anyway of getting the judges ruling overturned? and what is the first step in the process for that? Also, can I get it as time served since there was a warrant when I was incarcerated for the first charge? The sentence is obviously excessive and an abuse of power, can I do anything at all?
I have been ordered to show back up on christmas eve at 6 pm to serve my jail time. So time is not on our side, but if I cant get out of it, and still pursue a complaint against the county, then I will do that. Please let me know the best way to deal with this. No jail time, being the best, and filing a formal complaint being next to the best. thanks.