If you were stopped for not using your blinker in violation of the transportation code, that is a valid reason to stop you even if the charge later doesn't hold up. If the state doesn't have any evidence against you they will either be forced to drop the charge or you can hire an attorney and win at trial hopefully.
As for a lawsuit for wrongful arrest and harassment as far as I know of cases against police departments, to beat the immunity of the officers in their capacity as police officers you would need more facts to show they were not acting in good faith.
You need an attorney.
If you are being charged with a Class B or higher theft, and you cannot afford an attorney, you can ask the Court to appoint one to you.
The attorney can ask for a copy of the video and reports to prepare your case.